The present study was the first to use multi-level data from different databases to perform a CXCL13 expression-based pan-cancer analysis and the results indicate that CXCL13 can be used as a risk or prognostic factor for many cancers, and it plays an important role in tumor immunity by affecting TMB, MSI and tumor infiltrating immune cells. The gene discussed is CXCL13; the disease is cancer.