IDO1 and neoplasm: Another strategy for targeting multiple antitumor immune pathways to induce synergistic antitumor immunity was explored in vivo by Yan et al., involving the design of a platform that combined immunotherapy with PTT based on folic acid and a multifunctional IDO inhibitor loaded with reduced graphene oxide (rGO)-based nanosheets (IDOi/rGO nanosheets), which directly kill tumor cells under laser irradiation and trigger an in situ antitumor immune response.