Today, the world is witnessing remarkable advancements in the field of anti-cancer treatment. The latest on the list is “immunotherapy”. The concept of immunotherapy is based on boosting the body’s own immune cells to kill or control the growth of cancer cells. Unlike chemotherapy, where chemotherapy drugs kill cancer cells, immunotherapy drugs have no direct effect on the cancer cells. There are many types of anticancer immunotherapy drugs being tried in the trials. Cancer vaccines, oncolytic viral therapy, T cells, and immune checkpoint inhibitors are the ones that are most promising. Out of these, immune checkpoint inhibitors have gained maximum popularity. Currently, there is hardly any cancer where these drugs are not being tried in a clinical trial.