CTLA4 and melanoma: In a B16 mouse melanoma model, iNKT cells infiltrated tumors, but displayed dysfunctional states with increased expression of the exhaustion markers (including PD1, CTLA4, and TIM3) and of NKG2D, as well as low levels of IFNγ production associated with IL-4, IL-10, and IL-17 production within the TME (23).