This study aims to explore the common immune-related gene characteristics of cholangiocarcinoma (CHOL) and inflammatory bowel disease (IBD) to predict disease prognosis. By analyzing the gene expression data from the TCGA, GEO, and NGDC databases, differentially expressed immune-related genes (DE-IRGs) were screened, and a prognostic model was constructed. The results showed that CCR7, OSM, S100P, ACVR1C, OSMR, SPP1, and PIK3R3 were key immune-related genes, and their expressions were closely related to the occurrence and development of CHOL and IBD. Patients in the low immune risk score (IRS) group had more abundant antitumor immune cell infiltration, while those in the high IRS group had more macrophage infiltration. In addition, the model based on these genes had good predictive ability for the diagnosis and prognosis of CHOL and IBD, with an area under the ROC curve (AUC) value exceeding 0.7. This study also predicted potential small molecule drugs that might be effective for the treatment of CHOL, such as Umbralisib and Tamoxifen. In conclusion, this study provides new biomarkers and potential targets for diagnosis, prognosis assessment, and treatment of CHOL and IBD.