The present invention relates to an anticancer composition comprising a tumor-specific oncolytic adenovirus and an immune checkpoint inhibitor. The recombinant adenovirus having IL-12 and shVEGF, or IL-12 and GM-CSF-RLX inserted therein, according to the present invention, exhibits an excellent anticancer effect by enhancing immune functions, and such anticancer effect has been confirmed to be notably enhanced through concomitant administration with an immune checkpoint inhibitor, and thus the present invention may be used as a key technique in the field of cancer treatment.