Antitumor combination therapy is a strategy to mount a more successful attack on tumor growth. Significant suppression of tumor growth by enhancing cytotoxic T cell activation can be achieved with the combined use of an antitumor vaccine and immune checkpoint antibody treatment. The function of cancer vaccines include stimulating the immune system to mount an attack against tumor cells, as well as enhancing cytotoxic T cell reactions. However, checkpoint antibodies are treatments designed to inhibit factors that prevent the function of cytotoxic T cells. These factors represent one of the main weaponry used by cancer cells against immune system attack.