Beyond vaccines, beyond checkpoint inhibitors, chimeric antigen receptor T-cells (CAR T-cells) are the latest form of cancer therapies aimed at reestablishing the body’s immune response to tumors. Like the Chimera of Greek mythology, a hybrid creature composed of more than one animal, CAR T-cells are molecules engineered in the laboratory using a hybrid of proteins grafted onto a patient’s T-cells. The hybrid assembly allows the CAR T-cells to carry out multiple specific functions. This engineering allows CAR T-cells to recognize specific proteins, or antigens, present on the surface of targeted cancer cells, allowing the CAR T-cells to become activated and destroy the tumor.