In GC, pembrolizumab and nivolumab (both anti-PD-1 antibodies) have demonstrated survival benefit and gained regulatory approval in advanced settings; namely, pembrolizumab received accelerated approval for treatment of PD-L1-positive GC in third-line or later treatment by the US Food and Drug Administration (FDA) and for the treatment of patients with unresectable or metastatic, microsatellite instability-high (MSI-H), or mismatch repair-deficient (MMR-D) solid tumors that have progressed following prior treatment [118]. Here, PDCD1 is linked to gastric cancer.