Dissimilar to anti-PD-1 therapy to block T-cell inhibition to re-activate T cells, EGCG inhibited IFN-γ-induced JAK-STAT signaling and its downstream PD-L1/PD-L2 expression in human and mouse melanoma cells; thus, protecting T-cell exhaustion and enhancing their immune responses. Here, PDCD1 is linked to melanoma.