食管癌和胃癌都是预后不良的恶性肿瘤，但放射疗法，化学疗法和靶向疗法近年来在改善预后方面的进展有限。使用检查点抑制剂的免疫疗法是一种新的治疗方法，并迅速应用于治疗恶性黑色素瘤和肾细胞癌的临床实践中，但其在食管癌和胃癌中的作用仍然很难确定。目前免疫疗法效果的评价以及预测性生物标志物是程序性死亡受体-配体1(programmed cell death-ligand 1，PD-L1)的表达以及错配修复基因中的缺陷而导致微卫星不稳定性(microsatellite instability，MSI)表型。本综述总结了食管癌和胃癌中PD-L1和MSI状态的临床预后和预测作用以及潜在的临床意义。“,”Esophageal cancer and gastric cancer are malignant tumors with poor prognosis. Unfortunately, radiotherapy, chemotherapy and targeted therapy have made limited progress in improving prognosis in recent years. Immunotherapy using checkpoint inhibitors is a new treatment method. It has made some progress in the treatment of malignant melanoma and renal cell carcinoma, but its role in esophageal cancer and gastric cancer are still difficult to determine. At present, the evaluation of immunotherapy effect and the prediction of biomarkers are the expression of programmed cell death-ligand1(PD-L1) and the defects in mismatch repair genes which lead to microsatellite instability(MSI) phenotype. This review summarizes the clinical prognosis, prediction and potential clinical significance of PD-L1 and MSI.