To further corroborate the role of AhR activation, we used a potent AhR ligand, TCCD, to test its effect on anti‐CD40 (Figures S2C–S2F and S8A–S8K, Supporting Information) and DSS (Figures S2G–S2J and S9a–S9K, Supporting Information)‐induced colitis mouse models. The gene discussed is CD40; the disease is colitis.