Inhibitors targeting programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) have been successfully approved for the clinical treatment of various malignant tumors such as malignant lymphoma and non-small cell lung cancer (2–4). This evidence concerns the gene CTLA4 and lymphoma.