CTLA4 and gastric cancer: In recent years, although anti-cytotoxic T-lymphocyte associated protein 4 (anti-CTLA-4), anti-programmed cell death-1/programmed cell death-ligand 1 (anti-PD-1/PD-L1) antibody, chimeric antigen receptor (CAR) T-cell therapy and other targeted drugs have achieved certain clinical effects, but most patients with advanced GC still have low prognostic benefits, and the median survival is still less than 12 months3,4.