Combination immunotherapeutic strategies for cancer. The afferent or priming phase of the immune response may be enhanced by vaccines using novel tumor antigens or adjuvants or by vaccinating stem cell transplant (SCT) donors with healthy immune systems with the goal of adoptive transfer of the antitumor immunity to the patient. The efferent or effector phase of the immune response may be augmented by inhibiting various immunosuppressive and tolerance mechanisms in the tumor microenvironment. Potential strategies that are in various stages of preclinical and clinical development are shown. These agents may be used in combination with therapeutic cancer vaccines for optimal induction of antitumor immunity that, in turn, may lead to improved clinical outcome. MDSC, myeloid-derived suppressor cells; TGF-β, transforming growth factor beta.