The lexicon of oncology is filled with military metaphors: the war on cancer, aggressive tumors, magic bullets. And although these are indeed only metaphors, they do reflect an underlying attitude--that it is the clinician's job to attack and destroy his patient's tumor directly, with whatever weapons that come in handy. ＿＿（37）＿＿ There is even talk of biological agents, in the form of viruses specifically tailored to seek out and eliminate their tumorous targets. ＿＿（38）＿＿ But as Sun Tzu observed, the wisest general is not one who wins one hundred victories in one hundred battles, but rather one who overcomes the armies of his enemies without having to fight them himself. And one way to do that is to get someone else to do your fighting for you. 39 Instead of attacking cancer directly, immunotherapy recruits a patient's immune system to do the attacking. The latest way of doing so is by removing the controls which keep the immune system in check during times of bodily peace, let it damage the person it is supposed to be protecting. Now, as a series of papers presented in June 2013 to the annual meeting of the American Society of Clinical Oncology in Chicago shows, its range is being extended. ＿＿（40）＿＿ The treatment of melanoma that started the ball rolling employed a particular drug called ipilimumab, a monoclonal antibody.