PDCD1 and gastric cancer: However, only 9% absolute benefit is observed from adjuvant chemotherapy compared with the surgery-only group, and only 10–26% objective response rate is achieved in GC patients treated with immune checkpoint blockade (ICB), such as anti-programmed cell death protein 1 (PD-1) and anti-programmed death-ligand 1 (PD-L1) (4, 21–23).