> Neither of the vaccines prevents cancer; rather, they are a kind of immunotherapy that prompts the body’s immune system to battle the disease in patients with non-small cell lung cancer.

Not 100% sure, because I've only heard about vaccines in preventative contexts before, but based on this description my guess would be that "anything that tells your immune system to Do Stuff" counts as a vaccine. Versus something like Herceptin, which also treats cancer, just with ready-made antibodies that were grown in a lab.

There are also immune modulators that aren't vaccines. Interferon, for example, or more recently the famous checkpoint inhibitors that take the brakes off immune attack of cancer cells.