Immunotherapy is a cancer treatment that boosts the immune system to help destroy cancer cells using the body’s own immune system. It can be used alone or in combination with other cancer treatments. It is administered as an infusion through a port (a tube connected to a vein) or intravenously (IV) (medicine given through a needle into a vein). Use the NCI tool in the lower-right corner to search for terms you are unfamiliar with.