ICIs have revolutionized tumor therapy by specifically modulating inhibitory receptors (e.g., CTLA-4, PD-1, LAG-3, and TIM-3) and ligands (PD-L1) presented on immune and tumor cells, ultimately stimulating anti-tumor IVDR.267–269 Emerging preclinical evidence also emphasizes the role of gut microbiota in modulating the IVDR of ICIs treatment by influencing the immune response.235,238,263. Here, HAVCR2 is linked to neoplasm.