In functional assays, CD70 knockout CAR-NK cells mediated cytotoxicity against multiple CD70-positive tumor cell lines including AML and RCC both in vitro and in vivo . Conclusions Overall, the results demonstrate the potential for targeting CD70 with CAR-NK cell therapy for the treatment of AML, RCC, and other CD70-positive malignancies while overcoming fratricide issues by engineering with a non-viral transposon delivery system in combination with CRISPR/Cas9 editing.