IFNG and cutaneous melanoma: In this regard, IFNγ has been identified as the lynchpin factor in the induction and sustained expression of ICPs on tumor and infiltrating T cells in several tumor types and thus, qPCR detection of IFNγ has been considered a potential marker of response to ICP blockade in several cancer studies including in non-small cell lung cancer (NSCLC) and cutaneous melanoma (SKCM) (6–8).