Provided are a therapeutic agent comprising an oncolytic virus and CAR-NK cells, use, a kit and a method for treating tumors and/or cancers. The therapeutic agent comprises a first pharmaceutical composition, the first pharmaceutical composition comprising an oncolytic virus located in a first pharmaceutically acceptable carrier; and a second pharmaceutical composition, the second pharmaceutical composition comprising NK cells located in a second pharmaceutically acceptable carrier. The oncolytic virus can be selectively replicated in tumor cells. The surface of the NK cells is modified by a chimeric antigen receptor, and the chimeric antigen receptor comprises an antigen binding domain, a spacer region, a transmembrane region and an intracellular domain that are operably linked and sequentially tandem, the antigen-binding domain being from a ligand-binding region of NKG2D, the intracellular domain being from an intracellular signal region of DAP12.