The high intra- and inter-tumor heterogeneity of gastric cancer leads to a great difference in the immunotherapy efficacy and the prognosis among patients. Several biomarkers， including programmed death-ligand 1， human epidermal growth factor receptor 2， the features of tumor microenvironment， the peripheral blood inflammatory markers and Claudin18.2 have predictive value in the immunotherapy efficacy and the prognosis of gastric cancer patients， which might help the clinicians find the potential patients who will benefit from immunotherapy， and achieve the goal of precision medicine.