Abstract: Disclosed is the use of an IAP antagonist for pretreating a human subject diagnosed with a cancer to enhance the likelihood that a subsequent treatment with an anti-PD-1 molecule results in an anti-cancer response or to enhance the responsiveness of the subject's cancer to the subsequent treatment with the anti-PD-1 molecule. Also encompassed are methods of treatment of a subject's cancer, the methods comprising pretreatment of the subject with an IAP antagonist and subsequent treatment of the subject with an anti-PD-1 molecule.