Marcus Butler is a physician investigator with an interest in the translational development of immune-based therapies for cancer patients. He completed his Hematology/Oncology training at Dana-Farber/Partners CancerCare, Harvard Medical School, Boston. After serving on the Dana-Farber staff, he joined the Department of Medical Oncology and Hematology at the Princess Margaret Cancer Centre in 2012. He is a member of the medical oncology staff at Princess Margaret Cancer Centre, University Health Network, and Assistant Professor in Medicine and Immunology at the University of Toronto. He is the Melanoma/Skin Medical Oncology Site Lead at the Princess Margaret and is the Clinical Director for the Immune Profiling Team at the Princess Margaret. He is also the Medical Oncology Chair for the Melanoma Site for the Canadian Cancer Trials Group. His work focuses on the development of immunotherapy trials, which include studies, alone and in combination, of immune checkpoint blocking antibodies, immunomodulators, and adoptive cell transfer.