Currently, gastric cancer is treated by surgical resection combined with postoperative chemotherapy and immunotherapy. Immunotherapy has been highly expected, however, due to the complexity of tumor pathogenesis, the lack of in-depth understanding of tumor immune mechanism, as well as the obvious heterogeneity and diverse pathogenesis of gastric cancer, there are differences in the efficacy of various treatments on gastric cancer. However, the concept of immunotherapy is most in line with people’s expectation, especially in tumor prevention, prevention of recurrence and metastasis after tumor resection, etc. It has very positive significance. At present, there are quite a few research advances in tumor immunotherapy that are worthy of reference in gastric cancer treatment in order to make a breakthrough. 1. Immunotherapy based on effector T cells In the 1980s, many clinical and experimental studies on lymphokine-activated killer cells for tumor treatment were reported, but due to the limited understanding of antigen-presenting cells, LAK induced by IL-2 stimulation alone lacked the activation of specific antigens, the specificity of tumor recognition was not high, and the overall efficiency was low. Four years after the report of LAK, a new concept of tumor-infiltrating lymphocytes was proposed by Rosenberg et al. reported that TIL isolated from tumor tissues had 50-100 times higher in vitro anti-tumor efficiency than LAK. Koyama et al. applied TIL to treat 23 patients with progressive gastric cancer, with a clinical benefit rate of 34.8%. In order to improve the efficiency of TIL immune response, many scholars have made many useful attempts. mineharu et al. used T cell recoding strategy, thus enhancing the efficiency of T immunotherapy. 2. Dendritic cell-based immunotherapy A large number of studies have shown that DC is closely related to the progression, stage, invasion, metastasis and prognosis of gastric cancer, and there are many basic and clinical studies related to DC-based immunotherapy for gastric cancer. Tumor-associated antigens or tumor-specific antigens were used to stimulate DC to enhance the efficiency and specificity of immune response. These clinical studies showed that some of the tested gastric cancer patients showed a decrease in serum tumor index and mass shrinkage after receiving antigen-stimulated DC. In addition to the direct stimulation of DC maturation with antigens, DCs have also been transfected with RNA or cDNA of specific antigens by vectors, which are translated into peptides in DCs that are directly presented by the human major histocompatibility complex molecules. Animal studies have also demonstrated the effectiveness of DC vaccines in vivo. Subcutaneous immunization of mice with the mouse gastric cancer cell line MFC total RNA-loaded mouse spleen DC was effective in activating NK and CTL in vivo and significantly inhibited the growth of gastric cancer in vivo. And immunization of BALB/c mice with gastric cancer cell lysate loaded with p53 overexpression DC could similarly effectively inhibit the growth of gastric cancer in vivo in hormonal mice. 3.Immunotherapy based on DC combined with cytokine induced killer cells In recent years, the immunotherapy strategy of DC combined with cytokine induced killer cells through in vitro culture has gradually emerged, and the DC-CIK combination not only solves the problem of tumor antigen recognition and presentation, but also enhances the efficiency of DC-activated T cells by co-culture and sensitization of antigen-stimulated DC and CIK in vitro, and then transfusion back to the patient. The in vitro co-culture of DC and CIK not only reduces the amount of IL-2 used for CIK expansion, but also results in a larger number of killer cells with higher recognition efficiency. A randomized controlled clinical study of 110 postoperative gastric cancer patients also confirmed that patients in the DC-CIK combination chemotherapy group had significantly longer survival at both 3 and 5 years than the chemotherapy alone group. For inoperable stage IV patients, it also showed significant efficacy. 4. regulatory T cell-based immunotherapy Regulatory T cells are a special subpopulation of CD4+ T cells, mainly highly expressing CD25 and FoxP3. Treg has been found to be significantly increased in many tumor tissues and induces peripheral T cell immune tolerance through induction of activated cell death, incompetence or immune response regulation, which is an indicator of poor tumor prognosis. Therefore, removal of Treg is an important strategy for antitumor cellular immunotherapy. Currently, it is mainly achieved by two strategies: removal of CD25-positive cells by monoclonal antibodies or blocking the CTLA-4 inhibitory pathway on the Treg surface. Okita et al. added an anti-CD25 monoclonal antibody to LAK in vitro, and the proliferative capacity of LAK was significantly increased after Treg removal, and the ability of the killer T cells in it to kill gastric cancer cell lines was also significantly enhanced.Ralph et al. reported the use of an anti-CTLA-4 monoclonal antibody, tremelimumab, in second-line treatment of 18 patients with advanced gastric cancer, and one of them The patients had partial tumor remission and maintained it for 32 months, and 4 patients had stable disease. Although the results of this phase II clinical trial were not as significantly better than chemotherapy as expected, it has received much attention for its low toxicity and safety benefits.