Serplulimab is a monoclonal antibody designed to target and inhibit programmed cell death protein 1 (PD-1), a receptor on immune cells that plays a key role in regulating immune responses. Serplulimab binds to PD-1 on T cells, blocking its interaction with PD-L1 and PD-L2 ligands. This inhibition prevents the suppression of T cell activation and enhances the immune response against cancer cells. It is primarily used in the treatment of certain types of cancers, particularly those where the PD-1/PD-L1 pathway is exploited by cancer cells to evade immune surveillance. These include cancers such as non-small cell lung cancer (NSCLC), melanoma, and others.