NX-1607 (Cbl-b-IN-3) is an oral inhibitor of Casitas B-lineage lymphoma proto-oncogene B (CBL-B), which is an E3 ubiquitin ligase and a key regulator of T, NK, and dendritic cell activation and suppresses their anti-tumor functions. NX-1607 enhances antigen recall, reduces T cell exhaustion, and increases cytokine production in response to T cell receptor stimulation, thereby counteracting suppressive signals from the tumor microenvironment.