IDO1 and pancreatic neoplasm: In addition to CTLA4, which was highly expressed in the LRS group, APC_co_repression, CD274 (PD-L1), HAVCR2, IDO1, LAG3, PDCD1 (PD-1), TGFB3 and TIGIT were highly expressed in the HRS group, suggesting that the HRS group exhibited a significant immunosuppressive state and that the risk model could be used as a new marker for immunotherapy in pancreatic cancer.