Navoximod is primarily used in cancer immunotherapy research due to its ability to inhibit the IDO1 (indoleamine 2,3-dioxygenase 1) enzyme. By blocking IDO1, Navoximod helps prevent the suppression of T-cell activity in the tumor microenvironment, thereby enhancing the immune system's ability to recognize and attack cancer cells. It has been investigated in clinical trials as a combination therapy with immune checkpoint inhibitors such as anti-PD-1 or anti-CTLA-4 antibodies to improve treatment outcomes in various solid tumors, including melanoma and other advanced cancers. Its application aims to overcome immune resistance and boost the efficacy of existing immunotherapies.