IDO1 and neoplasm: Furthermore, sirpiglenastat enhances CD4+ and CD8+ T-cell function and decreases regulatory T-cell numbers (100), while JHU-083 promotes anti-tumor immunity by inducing apoptosis of MDSCs, stimulating the conversion of immunosuppressive macrophages and MDSCs into pro-inflammatory macrophages, and inhibiting the expression of IDO1 in both myeloid and tumor cells (101).