Disclosed herein are methods and compositions for enhancing an immune response to a solid tumor in a subject. In some embodiments, a method comprises: (a) administering to the subject a hypoxia-activated bioreductive agent (HABA)； (b) inducing hypoxia by (i) administering a hypoxia-inducing agent to the subject or (ii) embolizing one or more blood vessels supplying the solid tumor； and (c) administering an immune checkpoint inhibitor prior to, simultaneously with, or subsequent to step (b) in an amount effective to enhance an immune response to the solid tumor, as compared to an immune response in the absence of the immune checkpoint inhibitor. Kits for use in the disclosed methods are also provided.
