Surzebiclimab (BGB-A425) is a humanized IgG1 variant monoclonal antibody targeting T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), an immune checkpoint receptor. It binds to TIM-3 on T cells, NK cells, and myeloid cells to block its interaction with ligands (e.g., galectin-9, phosphatidylserine), thereby reversing immune exhaustion and enhancing anti-tumor activity. It is being developed for cancer immunotherapy, often in combination with anti-PD-1 antibodies, in advanced solid tumors and hematologic malignancies.