A monoclonal antibody directed against the inhibitor receptor lymphocyte activation gene-3 (LAG-3), with potential immunomodulating and antineoplastic activities. Upon administration, relatlimab binds to LAG-3 on tumor infiltrating lymphocytes (TILs). This may activate antigen-specific T-lymphocytes and enhance cytotoxic T cell-mediated tumor cell lysis, which leads to a reduction in tumor growth. LAG-3 is a member of the immunoglobulin superfamily (IgSF) and binds to major histocompatibility complex (MHC) class II. LAG-3 expression on TILs is associated with tumor-mediated immune suppression.