In addition to melanoma, large H22 hepatocellular carcinoma (7 × 7 mm) was also effectively treated by the combination of IFN-γ and 1-MT or DMF (Supplementary Fig. 8d,e), further demonstrating that IFN-γ and IDO1/AhR inhibitor have remarkable treatment efficiency. Here, IDO1 is linked to hepatocellular carcinoma.