AhR is considered a natural ligand for tryptophan derivatives.[20] Previous studies have shown that 3‐IAA can influence host immune regulation and metabolic homeostasis by activating the AhR signaling pathway.[21] Moreover, Tryptophan‐derived microbial metabolites have been shown to suppress anti‐tumor immune responses by activating the AhR in tumor‐associated macrophages.[22] Given that 3‐IAA is a member of this class of ligands, we hypothesized that its effects in bladder cancer are mediated via AhR signaling. This evidence concerns the gene AHR and urinary bladder cancer.