Our results showed that the expression level of L-4 increased in the plasma of the immunotherapy-resistant group, and patients with high levels of IL-4 had lower objective response rate (ORR) and shorter progression-free survival (PFS), and the effect of IL-4 on inhibiting mouse gastric cancer PD-1 antibody efficacy was verified by e in vivo experiment. This evidence concerns the gene IL4 and gastric cancer.