PDCD1 and melanoma: To generalize 11C-l-1MTrp PET imaging for monitoring the cancer-immune status and antitumor response in mice receiving different immunotherapies, we evaluated another cohort of immunocompetent melanoma-bearing mice that received a triple-treatment regimen of anti-programmed cell death 1 (PD-1, clone RMP1-14, 10 mg/kg) + anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4, clone 9H10, 5 mg/kg) + CPA (150 mg/kg) (figure 6A).