In this regard, in LLC cells in which exogenous Id1 (Id1-flag) was expressed independent of trametinib treatment, the trametinib-induced PD-L1 expression upon IFN-γ incubation was abolished and importantly, the trametinib and anti-PD-1 combined treatment did not modify the immunosuppressive tumor microenvironment. Here, PDCD1 is linked to neoplasm.