ABSTRACT
Gastric cancer is the most common gastrointestinal cancer in China. The morbidity and mortality are extremely high and there are significant challenges in the treatment of gastric cancer. Recent studies have shown that the expressions of T lymphocyte subsets vary in the immune microenvironment of gastric cancer patients. T lymphocytes are not only the main effector cells of human cellular immunity, but also the important immunoregulatory cells. T lymphocytes not only reflect the state of the tumor microenvironment, but also closely relate with the prognosis of patients. T lymphocytes play a crucial guiding role in the clinical treatment. Currently, clinical trials related to immunological checkpoint inhibitors are still underway, among which PD-1/PD-L1 monoclonal antibody has been approved for the treatment of gastric cancer. The applications of tumor vaccines and adoptive cell therapies in gastric cancer are also being explored. How to screen patients suitable to immunotherapy, develop the best combination therapy and evaluate the effectiveness of immunotherapy need to be studied and solved.