PDCD1 and neoplasm: For AGC, the humanized anti-programmed cell death-1 (PD-1) IgG4 monoclonal antibody pembrolizumab (pembro) is licensed as a second-line or later therapy for tumors with high microsatellite instability (MSI-H) or those with a high mutation rate (Tumor mutational burden-high:TMB-H) [4].