Herein, we engineered a new HER2-specific CAR composed of a PD-1 extracellular domain (sPD-1-CAR-NK cells) with the aim to improve the anticancer efficacy of HER2-CAR-NK cells for patients harboring cancer cells with high HER2 expression, especially for those with trastuzumab resistance. Here, ERBB2 is linked to cancer.