IDO1 and cancer: Upon entry into the TME, NLG and NO are sequentially excreted via GSH/ROS-mediated catabolism; NO release causes pyroptosis, which can release immunostimulatory cytokines and restore strong inflammatory effects, while NLG is activated to cut off the IDO pathway, which can reverse the immunosuppressive environment, simultaneously triggering pyroptosis and impeding IDO-associated immune escape for self-cascade amplification of antitumor immunotherapy, which will pave a new path for cancer immunotherapy (Hu et al., 2024).