MoS2 nanosheets and a doxorubicin (DOX)-containing poly(lactic-co-glycolic acid) (PLGA)/MoS2/DOX composite implant are successfully constructed based on the unique phase-changing behavior of PLGA/MoS2/DOX oleosol within tumors. The fast phase transformation can firmly restrict MoS2 and DOX within tumors, and the integrated MoS2 and DOX can endow the implant with high synergistic photothermal and chemotherapeutic efficiency against tumors.