Immunotherapy to Treat Cancer (2026): Types, Benefits, Risks, and Latest Breakthroughs
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Immunotherapy became widely known when former President Jimmy Carter’s medical team used it to treat his metastatic melanoma cancer. When the former president announced in August, 2015 that malignant tumors had been found in both his liver and his brain, most people presumed that he would be dead within months. But just four months later he surprised the world with the news that, following a remarkable and revolutionary new treatment, there was no sign of cancer in his body. The treatment he received was a drug classified as an “immune checkpoint inhibitor”. This class of medications has kicked off a revolution that has demonstrated that cancer can be cured by your own immune system. It just needs a little help. There are now countless drugs based on this principle.
- Introduction
- How does immunotherapy work against cancer?
- What are the types of immunotherapy?
- Which cancers are treated with immunotherapy?
- What are the side effects of immunotherapy?
- How is immunotherapy given?
- Where do you go for immunotherapy?
- How often do you receive immunotherapy?
- How can you tell if immunotherapy is working?
- What is the current research in immunotherapy?
- How do you find clinical trials that are testing immunotherapy?
Introduction
Together, these “cut, burn, and poison” techniques are estimated to cure cancer in about half of the people who develop the disease. That is a remarkable medical achievement. But it leaves the other half. Last year in the United States alone, nearly six hundred thousand people died of cancer.
The fight was never fair. We have been pitting simple drugs against endlessly creative, mutating versions of our own cells—trying to kill the bad ones while sparing the good ones, and often making ourselves sick in the process. And we have been doing this for a very long time.
Now, however, we have added a fourth and fundamentally different approach—one that does not act directly on cancer itself, but on the immune system.
The human immune system has evolved over more than 500 million years into a personalized and extraordinarily effective natural defense against disease. It is a complex biological system with a deceptively simple mission: to find and destroy anything that does not belong in the body. Hundreds of millions of immune cells are on constant patrol, circulating through blood and tissues, slipping in and out of organs, searching for and eliminating invaders that make us sick—as well as body cells that have become infected, mutated, or defective. Cells like cancer.
Which raises an obvious question: why doesn’t the immune system eliminate cancer on its own?
The answer is that it often does—or tries to. Cancer, however, uses sophisticated tricks to hide from immune surveillance, shut down immune defenses, and avoid destruction. Unless we change the rules of the fight, we do not stand a chance.
Cancer immunotherapy works by defeating those tricks. It unmasks cancer, releases the immune system’s natural restraints, and restarts the battle. It differs fundamentally from every previous cancer treatment because it does not act on cancer directly.
Instead, it unlocks the body’s own killer immune cells and allows them to do the job they were designed to do.
Cancer is us. It is the mistake that works.
Cells in the body routinely go rogue. Their DNA is damaged by sunlight, toxins, viruses, aging, inherited mutations, or sheer randomness. Most of these mutations kill the cell outright. A few survive and divide. Roughly 99.9 percent of the time, the immune system recognizes these abnormal cells and destroys them.
The problem is the remaining fraction—the one cell in ten thousand, or one in a million, that escapes detection. That single unrecognized cell can eventually kill us.
Cancer does not announce itself like the flu or any other infection. It does not sound an alarm in the body. There is no fever, no inflammation, no swollen lymph nodes—often not even a hint of illness. Instead, a tumor is discovered suddenly, an unwelcome guest that has been growing silently, sometimes for years. By the time it is found, it is often too late.
To many researchers, this apparent lack of immune response meant that trying to stimulate one was futile—because there was nothing to stimulate. Cancer was assumed to be too much a part of “self” to be recognized as “non-self.” The very idea of cancer immunotherapy seemed fundamentally flawed.
And yet, throughout history, physicians had documented rare cases of spontaneous cancer remission—tumors that inexplicably disappeared. In the pre-scientific era, these were attributed to miracles or magic. In reality, they were the result of an immune system that had somehow been fully awakened.
For more than a century, researchers tried and failed to reproduce these events through medicine. They attempted to vaccinate against cancer or trigger immune responses similar to those that conquered diseases like smallpox, polio, and influenza. There were moments of promise, but no reliable treatments.
By the year 2000, scientists had cured cancer in mice hundreds of times—yet still could not consistently translate those successes to humans. Most believed they never would.
That belief changed—suddenly and radically.
Even for physicians, the shift was nearly invisible until it arrived at the clinic door. One of the most influential modern books on cancer, The Emperor of All Maladies by Dr. Siddhartha Mukherjee, published in 2010, does not mention cancer immunotherapy at all. Yet just five months later, the first of a new generation of immunotherapy drugs received FDA approval.
These drugs became known as checkpoint inhibitors. They emerged from the discovery that cancer uses specific molecular “checkpoints”—a kind of secret handshake—to signal immune cells not to attack. Checkpoint inhibitors block that signal, preventing cancer from shutting down the immune response.
In December 2015, one of these drugs was used to treat former U.S. President Jimmy Carter. An aggressive cancer had spread to his liver and brain, and he was not expected to survive. Instead, his immune system cleared the cancer. News of the ninety-one-year-old president’s recovery stunned the world—and Carter himself. For many people, “that Jimmy Carter drug” was their first introduction to cancer immunotherapy.
But the true breakthrough is not any single drug. It is a series of discoveries that fundamentally redefined what cancer is, how it evades the immune system, and how it can be defeated. These insights changed outcomes for patients and opened an entirely new frontier in medicine.
For the first time, cancer treatment moved beyond cutting, burning, or poisoning—and toward treating the patient rather than the tumor.
Hype can be dangerous, and false hope can be cruel. New scientific revolutions often attract exaggerated expectations, especially when they promise relief from a disease that has touched nearly every life. But immunotherapy is not an anecdotal miracle or speculative theory. It is a class of proven medicines backed by solid data.
Today, only a handful of immunotherapies are widely available, and fewer than half of cancer patients respond to them. But when they do work, the results can be profound. Remissions are measured not in weeks or months, but in years—or lifetimes. These durable responses are unique to immunotherapy, though they are not guarantees. There is still work to be done to expand who benefits and to truly achieve cures.
The door, however, is now open.
Several immunotherapy pioneers have compared this moment to the discovery of penicillin. As a drug, penicillin immediately saved lives. As a scientific breakthrough, it redefined what medicine could do. Nearly a century later, antibiotics are an entire class of therapies that transformed human survival so completely we now take them for granted.
Immunotherapy’s “penicillin moment” was the discovery of how cancer hides from the immune system. The approval of the first checkpoint inhibitor reoriented scientific research and ignited a global surge in drug development. Today, hundreds of immunotherapy drugs are in clinical trials, with thousands more combinations under investigation. The pace is so rapid that regulators have had to create new fast-track pathways to keep up.
Major advances in cancer once arrived every fifty years. Immunotherapy made a generational leap almost overnight. Scientists now speak of “tidal waves” and “tsunamis” of progress. Rarely in modern medicine has change moved this fast.
It was this transformation that the Nobel Committee recognized in 2018 when it awarded the Nobel Prize in Physiology or Medicine to Dr. James P. Allison and Dr. Tasuku Honjo. Their discoveries revealed how cancer evades immune attack—and how that evasion can be reversed—“revolutionizing cancer treatment and fundamentally changing how cancer can be managed.”
For the first time in our long war with cancer, we finally understand the enemy, its tricks, and how we might win.
How does immunotherapy work against cancer?
Cancer cells frequently use mechanisms that suppress immune cells. Among them:
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Checkpoint proteins like PD-1 and CTLA-4 act as “off-switches” on T cells; tumors co-opt them to evade immune attack.
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Checkpoint inhibitors block these switches, enabling T cells to recognize and destroy cancer cells. PubMed
This approach has been described as “releasing the brakes” on the immune system.
Even though the immune system can prevent or slow cancer growth, cancer cells have ways to avoid destruction by the immune system. For example, cancer cells may:
- Have genetic changes that make them less visible to the immune system.
- Have proteins on their surface that turn off immune cells.
- Change the normal cells around the tumor so they interfere with how the immune system responds to the cancer cells.
Major Types of Cancer Immunotherapy
Several types of immunotherapy are used to treat cancer. These include:- Immune checkpoint inhibitors, which are drugs that block immune checkpoints. These checkpoints are a normal part of the immune system and keep immune responses from being too strong. By blocking them, these drugs allow immune cells to respond more strongly to cancer. Learn more about immune checkpoint inhibitors.
- T-cell transfer therapy, which is a treatment that boosts the natural ability of your T cells to fight cancer. In this treatment, immune cells are taken from your tumor. Those that are most active against your cancer are selected or changed in the lab to better attack your cancer cells, grown in large batches, and put back into your body through a needle in a vein. T-cell transfer therapy may also be called adoptive cell therapy, adoptive immunotherapy, or immune cell therapy. Learn more about T-cell transfer therapy.
- Natural killer (NK) cell-based immunotherapies are attracting increasing interest in the field of cancer treatment. Early clinical trials have shown promising outcomes, alongside satisfactory product efficacy and safety. Learn more about Natural Killer Cells immunotherapy.
- Monoclonal antibodies, which are immune system proteins created in the lab that are designed to bind to specific targets on cancer cells. Some monoclonal antibodies mark cancer cells so that they will be better seen and destroyed by the immune system. Such monoclonal antibodies are a type of immunotherapy. Monoclonal antibodies may also be called therapeutic antibodies. Learn more about monoclonal antibodies.
- Treatment vaccines, which work against cancer by boosting your immune system’s response to cancer cells. Treatment vaccines are different from the ones that help prevent disease. Learn more about cancer treatment vaccines.
- Immune system modulators, which enhance the body’s immune response against cancer. Some of these agents affect specific parts of the immune system, whereas others affect the immune system in a more general way. Learn more about immune system modulators.
Which cancers are treated with immunotherapy?
Immunotherapy drugs have been approved to treat many types of cancer. However, immunotherapy is not yet as widely used as surgery, chemotherapy, or radiation therapy. To learn about whether immunotherapy may be used to treat your cancer, see the PDQ® adult cancer treatment summaries and childhood cancer treatment summaries.
What are the side effects of immunotherapy?
Immune-related adverse events (irAEs)
Unleashing the immune system can cause it to attack normal tissues. Common irAEs include:
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Skin rash, fatigue, diarrhea
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Endocrine disorders (e.g., thyroiditis)
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Hepatitis, pneumonitis
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Less common but serious autoimmunity can occur. journal.hep.com.cn
These effects are not usually lethal when properly managed — and oncologists today have well-established protocols to monitor, diagnose, and treat irAEs.
Cytokine release syndrome (CRS)
Seen primarily with CAR-T therapy, CRS results from massive immune activation. Controlled use of steroids and IL-6 blockers mitigate risks.
Learn more about immunotherapy side effects.
Related: Cardiac Toxicity Associated with Immune Checkpoint Inhibitors: Case Series and Review of the Literature (2019)
How is immunotherapy given?
Different forms of immunotherapy may be given in different ways. These include:
- intravenous (IV): The immunotherapy goes directly into a vein.
- oral: The immunotherapy comes in pills or capsules that you swallow.
- topical: The immunotherapy comes in a cream that you rub onto your skin. This type of immunotherapy can be used for very early skin cancer.
- intravesical: The immunotherapy goes directly into the bladder.
Where do you go for immunotherapy?
You may receive immunotherapy in a doctor’s office, clinic, or outpatient unit in a hospital. Outpatient means you do not spend the night in the hospital.
How often do you receive immunotherapy?
How often and how long you receive immunotherapy depends on:
- your type of cancer and how advanced it is
- the type of immunotherapy you get
- how your body reacts to treatment
You may have treatment every day, week, or month. Some types of immunotherapy given in cycles. A cycle is a period of treatment followed by a period of rest. The rest period gives your body a chance to recover, respond to immunotherapy, and build new healthy cells.
How can you tell if immunotherapy is working?
You will see your doctor often. He or she will give you physical exams and ask you how you feel. You will have medical tests, such as blood tests and different types of scans. These tests will measure the size of your tumor and look for changes in your blood work.
What is the current research in immunotherapy?
Researchers are focusing on several major areas to improve immunotherapy, including:
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Finding solutions for resistance.
Researchers are testing combinations of immune checkpoint inhibitors and other types of immunotherapy, targeted therapy, and radiation therapy to overcome resistance to immunotherapy. -
Finding ways to predict responses to immunotherapy.
Only a small portion of people who receive immunotherapy will respond to the treatment. Finding ways to predict which people will respond to treatment is a major area of research. -
Learning more about how cancer cells evade or suppress immune
responses against them.
A better understanding of how cancer cells get around the immune system could lead to the development of new drugs that block those processes. - How to reduce the side effects of treatment with immunotherapy.
Immunotherapy cancer success rate
Major Successes
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Melanoma, lung, kidney, bladder, and some head/neck cancers now routinely use checkpoint inhibitors.
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Combination immunotherapy (e.g., nivolumab + ipilimumab) has improved long-term survival in melanoma and other tumors. Frontiers
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Recent trials have shown complete remissions in select cancers (e.g., MMR-deficient rectal cancer) with immunotherapy alone. Adelaide Now
Expanding Use
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Immunotherapy is increasingly integrated with chemotherapy and radiation.
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Biomarkers such as PD-L1 expression and tumor mutation burden (TMB) help predict which patients are most likely to benefit. PubMed
Immunotherapy Fails When Certain Microbes Are Absent
Researchers have also explored the influence of gut bacteria on cancer patients' responses to checkpoint inhibitors — a class of immunotherapy drugs that work by triggering your immune system to attack cancer cells. However, this treatment has a fairly low success rate. Only 20% to 40% of patients respond to the treatment, and researchers began suspecting the gut microbiome might be the key to success or failure.Indeed, as reported in Nature, a 2015 study found that while microbe-free mice failed to respond to treatment with checkpoint inhibitors, mice given Bacteroides fragilis fared much better. Other researchers have had similar findings, showing Bifidobacterium improves the effectiveness of cancer immunotherapy in lab animals — again by triggering a more robust response by specific anticancer immune cells.
As you might expect, antibiotic treatment has been found to worsen response to immunotherapy, likely because antibiotics indiscriminately kill all gut bacteria, thereby ridding your body of many really important immune helpers. Importantly, even cancer therapies that do not rely on the activation of your immune response typically fail unless you have the appropriate gut microbes. (source)
For example, certain chemotherapy agents actually rely on gut microbes to eradicate the tumor directly. In other instances, the microbes' influence on cancer is related to their ability to influence gene expression alter the stability of your genes.
Latest Research and Future Directions
Next-generation immune strategies
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Targeting additional checkpoints beyond PD-1 and CTLA-4. Springer
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Combination therapies (e.g., dual checkpoint blockade, checkpoint inhibitors + radiation). Frontiers
mRNA vaccines and cancer
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Early data suggest that mRNA vaccines (like COVID-19 mRNA vaccines) might enhance responses in some patients, potentially by boosting immune activation during immunotherapy. The Washington Post
Biomarkers and AI
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Biomarker development and AI-based prediction models are helping tailor treatments to individuals more effectively. arXiv
How do you find clinical trials that are testing immunotherapy?
To find clinical research studies that involve immunotherapy visit Find NCI-Supported Clinical Trials or call the Cancer Information Service, NCI’s contact center, at 1-800-4-CANCER (1-800-422-6237).Conclusion — Hope Grounded in Science
Cancer immunotherapy has shifted from experimental to foundational in oncology. While it carries risks, those are well characterized and manageable in clinical settings, and the benefits have been proven in numerous serious cancers.
Source and Reference: https://www.cancer.gov/about-cancer/treatment/types/immunotherapy
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