Abstract: Visfatin, also known as nicotinamide phosphoribosyl transferase (NAMPT) or pre-B-cell colony-enhancing factor, is a proinflammatory adipokine. Its immunomodulatory effects are closely associated with its pro-inflammatory activity, influencing the secretion of various cytokines and the function of immune cells. Visfatin exerts pro-tumorigenic effects in most cancers. The tumor immune microenvironment (TIME) comprises immune cells within the tumor tissue and an array of secreted cytokines. Growing evidence suggests that visfatin plays a regulatory role in the TIME by promoting inflammatory responses and modulating the polarization of immune cells, their secretory functions, surface protein expression, and energy metabolism, thereby influencing cancer progression. These newly discovered mechanisms provide a critical foundation for the application of NAMPT inhibitors (NAMPTi) in cancer immunotherapy. This review summarizes recent advances in understanding the role of visfatin in tumor immunology and explores the therapeutic potential of NAMPTi in oncology.