Erfonrilimab is a humanized bispecific monoclonal antibody directed against programmed cell death-1 ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), with potential immune checkpoint inhibitory and antineoplastic activities. It is used to treat solid tumors and exhibits promising efficacy in advanced non-small cell lung cancer (NSCLC) patients who had experienced failure or intolerance to prior platinum-based chemotherapy. MW: 107.44 KD.