PDCD1 and melanoma: We studied the combination of CM-272 with PD-1 blockade therapy (2.5mg/kg intraperitoneal, on day 7, 14 and 21), which we reasoned could counteract CM-272-induced PD-L1 upregulation and thereby ameliorate the narrow therapeutic window for PD-1/PD-L1 blockade in melanoma subsets (37–39, 53).