Abstract: Gastric cancer is among the most common malignant tumors worldwide. Due to its subtle early symptoms and suboptimal screening rates, a significant proportion of patients are diagnosed with advanced-stage gastric cancer, which adversely influences patient prognosis. In recent years, with the advancement of research, immunotherapy for gastric cancer has made significant strides, demonstrating particularly remarkable efficacy in cases of unresectable and metastatic gastric cancer. This has established it as an effective treatment method following surgery, chemotherapy, radiotherapy, and targeted therapy. Immunotherapy involves artificially modulating the immune system using strategies such as adoptive cell therapy, immune checkpoint inhibitors, and tumor vaccines. Although immunotherapy has broad prospects, it faces many challenges and problems in clinical application. This review delineates the clinical application of immunotherapy in gastric cancer and discusses the extant challenges therein.