When illness strikes, white blood cells are the first cells on the scene. Much like a team of superheroes they each complete their specialized task, engulfing bacteria, controlling the immune response, and cleaning up dead or damaged cells. Leading the charge, is the macrophage, which literally translates to “big eater”. These white blood cells destroy illnesses, recruit other immune cells, and clean up the aftermath. Given their incredible power to heal us, researchers at the University of Wisconsin–Madison are exploring ways that these cells can be used to fight tumors through immunotherapy.