Abstract: Gallbladder cancer is a kind of common biliary tract tumor with high malignancy and poor prognosis. In recent years, many studies have shown that microsatellite instability (MSI) may be one of the mechanisms of gallbladder carcinogenesis. High frequency microsatellite instability (MSI-H) gallbladder cancer has a better therapeutic effect by treatment with an immunological checkpoint inhibitor due to its unique clinicopathological features. The general characteristics and the detection methods of MSI, clinicopathological features of gallbladder cancer, treatment of programmed cell death 1/programmed cell death ligand 1 immunological checkpoint inhibitors with MSI have been reviewed in this article.