Our immune systems have the potential to find and destroy cancer cells. But cancer cells can be clever and develop tricks to evade the immune system. Cold Spring Harbor Laboratory Professor Douglas Fearon and his former postdoc ZhiKai Wang found one such trick. Cancer cells weave a deactivating signal into a protective coat of armor that excludes T cells that would otherwise kill them. This immune deactivation pathway offers a promising new therapeutic approach for pancreatic, breast, and colorectal cancers.