IDO1 TDO-IN-3 is a powerful inhibitor targeting IDO1 and TDO enzymes. It displays noteworthy effectiveness against IDO1 (IC50: 0.005 μM) and TDO (IC50: 0.004 μM). Additionally, IDO1 TDO-IN-3 demonstrates considerable in vivo anti-tumor properties while exhibiting no apparent toxicity [1].