Urelumab is a monoclonal antibody used in cancer immunotherapy. It targets the 4-1BB receptor, a protein found on the surface of certain immune cells, especially T cells. By activating this receptor, urelumab enhances the immune system’s ability to recognize and destroy tumor cells. It has been investigated in clinical trials for various cancers, including melanoma, lymphoma, and solid tumors. The antibody helps boost T cell proliferation, survival, and cytokine production, leading to stronger anti-tumor responses. Due to its potent immune-stimulating effects, research focuses on optimizing dosing to balance efficacy and safety, particularly managing liver-related side effects. Urelumab is also being studied in combination with other immunotherapies, such as checkpoint inhibitors, to improve overall treatment outcomes. Its role in co-stimulating immune responses makes it a valuable tool in developing next-generation cancer therapies.