Matthias Kloor is a physician-scientist, deputy director and group lead at the department of Applied Tumor Biology, Heidelberg University Hospital, Clinical Cooperation Unit Applied Tumor Biology, German Cancer Research Centre (DKFZ), Heidelberg, Germany. As a physician scientist he has been working in the field of molecular pathology, tumor immunology, and pathogenesis of hereditary cancer for more than two decades. His research interests are dedicated to molecular models of tumor formation and their transfer into the clinical application, with a main focus on tumor immunology and immunological approaches for cancer prevention and treatment. His research during the last 10 years as leader of the research group ‘Immune biology of microsatellite-unstable cancer’ has been focused on the identification of relevant neoantigens specifically generated in microsatellite-unstable (MSI) cancers. These research activities have led to the first-in-human clinical trial examining a frameshift peptide neoantigen vaccine in MSI-H cancer patients. He complements the studies on cancer vaccines by examining mechanisms of immune evasion that allow MSI-H tumors to develop in spite of pronounced anti-tumoral immune responses.