The immune system is our body’s most powerful weapon to combat pathogens and cancer cells. However, tumor cells have a repertoire of tricks to evade the immune response. The divisions of the Research Program Tumor Immunology investigate the mechanisms regulating the behavior of immune cells. Research work focuses on cell proliferation and programmed cell death (apoptosis) as well as on the activation and regulation of immune cells. Also under investigation are cancers affecting the immune system as such. The aim is to better understand the role of the immune system in cancer, AIDS, and autoimmune diseases. The findings will be translated into new approaches for clinical application to utilize the potential of the immune system for fighting cancer.