Single-cell analysis revealed macrophages as key cells in BLCA, which were classified into five subtypes, with CALR, SLMAP, and PFKFB4 influencing their expression.<h4>Conclusion</h4>Four mannose metabolism-related prognostic genes were identified in BLCA, and macrophages were confirmed as critical cells. The gene discussed is CALR; the disease is bladder transitional cell carcinoma.