Traditional cancer therapies (such as chemotherapy and radiation therapy) have shown widespread success against various cancer types, but are known to have toxic, undesirable side effects as they do not selectively kill cancer cells and therefore actively damage healthy cells as well. This is where immunotherapy comes into play. Immunotherapy is a form of therapy that uses the body’s own immune system to fight the cancer within it. Think of your body as a battlefield and your immune system the frontline of soldiers, ready to attack foreign invaders. The problem with cancer cells is that they are not easily recognized as foreign pathogens (such as viruses or bacteria) because they originate in the host’s body and mutate from normal cells. It has long been postulated that the immune system could be used to target and kill cancer cells, but the process of figuring out how to harness this ability is not a simple task.