Abstract: Pancreatic ductal adenocarcinoma is a malignant digestive system tumor, which is very difficult to diagnose and treat. In recent years, tumor immunotherapy has achieved encouraging therapeutic effects in multiple types of tumor, such as melanoma, bladder cancer, breast cancer, non-small cell lung cancer and kidney cancer. However, immunotherapy strategies of pancreatic cancer still need to be further explored. Various immunotherapy strategies have been designed for the unique tumor microenvironment of pancreatic cancer, including autoimmune response enhancement (immunomodulators, monoclonal antibodies, tumor vaccines, cell therapy) and tumor immune escape suppression (immune checkpoint inhibitors, tumor microenvironment). In this article, we review the research progress of immunotherapy in pancreatic cancer, focus on the application of PD-1/PD-L1 inhibitors in pancreatic cancer, and analyze the prospects of immunotherapy combined with other methods to treat pancreatic cancer.