A method is disclosed for treating a cancer in a subject. The method comprises administering to the subject a composition comprising a therapeutically effective amount of a checkpoint inhibitor and a therapeutically effective amount of a tumor vaccine. In some embodiments, the tumor vaccine comprises radiated autologous tumor cells and a cell line engineered to express GM-CSF and CD40 ligand. In some embodiments, the checkpoint inhibitor comprises an anti-PD-1 antibody (e.g., BMS 936558), anti-PD-L1 antibody (e.g., cloneM1H1), anti-CTLA-4 antibody (e.g., Ipilimumab, BMS), or any combination thereof.