PDCD1 and melanoma: A retrospective analysis of patients with melanoma and CRC who did not respond to anti-CTLA-4 or anti-PD-1 therapy revealed these patients had tumors with gene mutations, including JAK1/2 and IFN-γ receptor 1/2 (IFNγR1/2), which are critical for IFN-γ signaling [330,331].