IDO1 and neoplasm: Combination strategies further enhance therapeutic efficacy: pairing metabolic inhibitors with chemotherapy (such as PKM2 inhibitors combined with 5-FU), immunotherapy (including IDO1 inhibitors used in conjunction with anti-PD-L1 agents), or radiotherapy (for example, SCD1 inhibitors administered alongside ferroptosis inducers) can synergistically amplify anti-tumor effects.