Unlike CAR-NK cell therapy, which expresses CAR on NK cells to mediate the targeted killing of tumour cells, NK cell engagers (NKCEs) consist of a single-chain fragment variable (scFv) of antibodies against NK cell activation receptors (e.g., CD16, NKp30, NKp46, and NKG2D) and one (Bispecific killer engagers, BiKEs) scFv of antibodies against different tumour antigens [228]. Here, KLRK1 is linked to neoplasm.