IDO1 and cancer: In the context of liver cancer, particularly hepatocellular carcinoma (HCC), the expression of AhR, along with indoleamine 2,3-dioxygenase-1 (IDO-1), kynurenine, and PD-L1, has been correlated with poor prognosis, indicating that the AhR pathway may also play a role in cancer progression and immune evasion [108].