ABSTRACT
Immunotherapy is a new anti-tumor method. The application of immune checkpoint inhibitor greatly improves the survival benefit for patients, but the drug resistance of immunotherapy affects the efficacy. Therefore, it is very important to explore the mechanism of drug resistance and solve the problem of drug resis-tance in tumor immunotherapy. Hypoxia in tumor microenvironment is the key factor of immune drug resistance. Hypoxia can inhibit the immune cells function and lead to immune escape through various mechanisms. It can be the breakthrough for overcoming the immunotherapy drug resistance that blocking pathway of hypoxia to promote immune resistance. By reviewing the mechanism of immunotherapy drug resistance induced by hypoxia, it is helpful to explore the development prospect of hypoxia-inducible factor-1α (HIF-1α) related targeted drugs in clinical application for immunotherapy.