Immunotherapy is treatment that uses certain parts of a person’s immune system to fight diseases such as cancer. This can be done in a couple of ways:

• Stimulating, or boosting, the natural defenses of your immune system so it works harder or smarter to find and attack cancer cells.
• Making substances in a lab that are just like immune system components and using them to help restore or improve how your immune system works to find and attack cancer cells.

In the last few decades immunotherapy has become an important part of treating some types of cancer. New immunotherapy treatments are being tested and approved, and new ways of working with the immune system are being discovered at a very fast pace. Immunotherapy works better for some types of cancer than for others. It’s used by itself for some of these cancers, but for others it seems to work better when used with other types of treatment.