What is immunotherapy?

Immunotherapy uses our immune system to fight cancer. It works by helping the immune system recognise and attack cancer cells.

You might have immunotherapy on its own or with other cancer treatments. Immunotherapy is a standard treatment for some types of cancer. And it is in trials for other types of cancer.

There are different types of immunotherapy. These include monoclonal antibodies, checkpoint inhibitors, and vaccines. Some types of immunotherapy are also called targeted treatments or biological therapies. 

The immune system and immunotherapy

Our immune system works to protect the body against infection, illness and disease. It can also protect us from the development of cancer. 

The immune system includes the lymph glands, spleen and white blood cells. Normally, it can spot and destroy faulty cells in the body, stopping cancer developing. But a cancer might develop when:

  • the immune system recognises cancer cells but it is not strong enough to kill the cancer cells
  • the cancer cells produce signals that stop the immune system from attacking it
  • the cancer cells hide or escape from the immune system

Immunotherapy helps our immune system to fight cancer. There are different types of immunotherapy treatments. These work in different ways to help our immune system recognise and attack cancer cells.

Why might you have immunotherapy?

Immunotherapy is not suitable for all types of cancers. But it is one of the main treatments for a few types. 

Researchers are also looking at immunotherapy in clinical trials for some types of cancer.

You can have immunotherapy on its own or in combination with other treatments such as surgery, chemotherapy or radiotherapy.

Whether you have immunotherapy depends on:

  • the type of cancer you have
  • how far your cancer has spread (the stage) 
  • other cancer treatments you’ve had


Before you have some types of immunotherapy you might need to have tests using some of your cancer cells or a blood sample. This is to find out whether the treatment is likely to work. These tests look for changes in certain proteins or genes. 

Your cancer specialist can tell you if this applies to your treatment. This is not the case for all immunotherapies and you don’t always need this test.

To test your cancer cells, your specialist needs a sample (biopsy) of your cancer. They might be able to use some tissue from a biopsy or operation you have already had.  

Types of immunotherapy

Immunotherapy treatments do not always fit easily into a certain type or group of treatments. This is because some drugs or treatments work in more than one way and belong to more than one group. So you might hear the same drug or treatment called different things.

For example, a type of immunotherapy called checkpoint inhibitors are also described as a monoclonal antibody or targeted treatment.

We have pages about the following immunotherapies:

  • monoclonal antibodies
  • checkpoint inhibitors
  • vaccines
  • cytokines
  • CAR-T cell therapy.

Ask your specialist about immunotherapy. They can explain:

  • whether this treatment is suitable for you
  • what the aim of treatment would be
  • what it would involve and the side effects

Monoclonal antibodies (MABs)

Antibodies are found naturally in our blood and help us to fight infection. MAB therapies mimic natural antibodies but are made in a laboratory. Monoclonal means all one type. So each MAB therapy is a lot of copies of one type of antibody.

MABs recognise and attach to specific proteins on the surface of cancer cells. Many different MABs are available to treat cancer. They work in different ways and some work in more than one way. 

MABs work as an immunotherapy in different ways. They might do one of the following:

  • trigger the immune system
  • help the immune system to attack cancer

Checkpoint inhibitors

Checkpoint inhibitors are MABs that work by helping the immune system attack cancer cells. Cancer can sometimes push a stop button on the immune cells, so the immune system won’t attack them. Checkpoint inhibitors block cancers from pushing the stop button.

Vaccines to treat cancer

Researchers are looking at whether vaccines can help the immune system to recognise and attack cancer cells.

In the same way that vaccines work against diseases, the vaccines are made to recognise proteins that are on particular cancer cells. This helps the immune system to recognise and mount an attack against those particular cancer cells.


Cytokines are a group of proteins in the body that play an important part in boosting the immune system.

Interferon and interleukin are types of cytokines found in the body. Scientists have developed man made versions of these to treat some types of cancer.

CAR T-cell therapy

This treatment changes the genes in a person’s white blood cells (T cells) to help them recognise and kill cancer cells. Changing the T cell in this way is called genetically engineering the T cell.

It is available as a possible treatment for some children with leukaemia and some adults with lymphoma. People with other types of cancer might have it as part of a clinical trial. 

This page is due for review. We will update this as soon as possible.

  • Recognizing and managing on toxicities in cancer immunotherapy
    LYang and others
    Tumour Biology. 2017, Volume 39, Issue 3:1010428317694542

  • Cancer: Principles and Practice of Oncology (10th edition)
    VT De Vita, TS Lawrence and SA Rosenberg
    Lippincott, Williams and Wilkins, 2015

  • State of the art in anti-cancer mAbs
    SM Chiavenna and others
    Journal of Biomedical Science, 2017. Volume 24, Issue 15

  • Clinical development of targeted and immune based anti-cancer therapies
    N A Seebacher and others
    Journal of Experimental Clinical Cancer Research 2019 Apr 11: 38 (1): 156

  • Cancer immunotherapy: broadening the scope of targetable tumours
    J Bulk and others
    Open Biology 2018 Jun 8(6) 180037.

  • Electronic Medicines Compendium 
    Accessed January 2021

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in.

Last reviewed: 
20 Jan 2021
Next review due: 
17 Jan 2024

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