With several FDA/EMA-approved monoclonal antibodies (mAbs) targeting programmed death receptor (PD-1) or its ligand (PD-L1), cytotoxic T lymphocyte antigen 4 (CTLA-4), and lymphocyte-activation gene 3 (LAG-3), ICIs are widely used in clinical practice for several tumor types, including melanoma, lung cancer, lymphoma, and renal cell carcinoma 1, 4-6. The gene discussed is CTLA4; the disease is neoplasm.