PDCD1 and gastric cancer: As such, we conducted the real-world study to evaluate the clinical effect and safety of this new regimen: intra-arterial chemotherapy with sequential anti-PD-1 monoclonal antibody in conversion therapy for patients with unresectable GC, and to dissect the alteration of TIME pro- and post- intra-arterial chemotherapy in order to detect possible scientific basis underlying the combination treatment.