The present invention is directed to compositions and methods of treating proliferative disorders, such as cancer, using a composition comprising an immune checkpoint antagonist and an antigen. It has been found that the composition elicits an immune response allowing an otherwise suppressed immune system to activate in order for T cells to attack cancer cells. Compositions may be presented in a vector comprising nucleic acids encoding the antagonist and antigen, and may include gene editing systems, such as CRISPR-Cas9 system.
