KLRK1 and leukemia: NK cells derived from NK cell lines, donor or autologous peripheral blood mononuclear cell (PBMC) and umbilical cord blood have been modified to express CARs against different cancer targets, including CD7, CD19, CD22, CD33 for lymphoma and leukemia, HER2 for glioblastoma, MUC1 for HCC (NCT02839954) and NKG2D for metastatic solid tumors (NCT03415100) [10,78,79].