Information BAY-218 BAY-218 is a potent and selective small-molecule AhR inhibitor, inhibiting AhR nuclear translocation, dioxin response element (DRE)-luciferase reporter expression and AhR-regulated target gene expression induced by both exogenous and endogenous AhR ligands. Targets AhR In vitro Mechanistically, BAY-218 inhibits AhR nuclear translocation, dioxin response element (DRE)-luciferase reporter expression and AhR-regulated target gene expression induced by both exogenous and endogenous AhR ligands. BAY-218 rescues TNFα production from kynurenic acid(KA)-suppressed LPS-treated primary human monocytes. In vivo BAY-218 enhances anti-tumoral immune responses and reduced tumor growth in the syngeneic mouse tumor models CT26 and B16-OVA. Furthermore, BAY-218 enhances therapeutic efficacy of an anti-PD-L1 antibody in the CT26 model.