EGFR and osteosarcoma: In spite of the limited availability of specific tumor antigen in solid tumors, such as HER2 and EGFR (or EGFR variant III) on breast cancer and glioblastoma [212,213,214,215,216], CS1 and CD138 on myeloma [217,218], GD2 on neuroblastoma [219,220] or NKG2D ligand on ovarian cancer and osteosarcoma [221,222], the application of CAR-NK therapies achieves impressive outcomes in the preclinical studies, without causing severe adverse effects like those by CAR-T therapies.