Cancer immunotherapy has gained a lot of interest over the past few years due to the success of immune checkpoint inhibitors in treating cancer (1, 2). Immune checkpoint inhibitors, such as monoclonal antibodies against cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4) and programmed death 1 (PD-1), have been shown to increase survival of patients with advanced cancers (1, 2). These in...