Immuno-oncology, known as Cancer immunotherapy, is a type of biotherapy that uses components from live organisms to treat cancer. It is also known as biologic therapy or biological response modifier (BRM) therapy. It's a cancer treatment that harnesses the body's immune system's potential to prevent, control, and eliminate cancer. It trains the immune system to recognise and target specific cancer cells, boosts immune cells to aid in cancer elimination, and provides the body with extra components to improve the immunological response. Targeted antibodies, cancer vaccines, adoptive cell transfer, tumor-infecting viruses, checkpoint inhibitors, cytokines, and adjuvants are just a few examples. Gene therapies are immunotherapy treatments that use genetic engineering to improve immune cells' cancer-fighting capabilities. Many immunotherapy treatments for cancer prevention, management, or treatment can be combined with surgery, chemotherapy, radiation, or targeted therapies to boost their efficacy. Immunotherapies have been licenced in various parts of the world for the treatment of a range of malignancies, and oncologists prescribe them to patients. These approvals are the product of years of research and testing to prove that these medicines are beneficial. Clinical trials, which are tightly regulated and monitored research including patient volunteers, are also accessible for immunotherapies. Immunotherapy does not always effective for every patient, and some forms of immunotherapy are linked to serious but treatable adverse effects. Scientists from companies such as AstraZeneca, Inc., Amgen, Bristol-Myers Squibb, Eli Lilly, Johnson & Johnson, Merck & Co., Novartis, Pfizer Inc., and startups such as Moderna Therapeutics, ADC Therapeutics, and Kymera Therapeutics are working on ways to predict which patients will respond to treatment and which will not. Immunotherapy is already helping to lengthen and save the lives of many cancer patients, despite the fact that scientists haven't fully understood the immune system's cancer-fighting powers. Immunotherapy has the potential to be more accurate, individualised, and successful than current cancer treatments, with fewer side effects.