KLRK1 and ovarian cancer: A CAR-NK cell containing the transmembrane domain of NKG2D, the 2B4 co-stimulatory domain, and the CD3ζ signaling domain significantly inhibited tumor growth and prolonged survival compared with peripheral blood NK cells, induced pluripotent stem cell (iPSC) NK cells, or CAR-T-iPSC-NK cells in an ovarian cancer xenograft model [74].