CD274 and cancer: To evaluate whether PD-L1.BB CSR engagement enhances the cytotoxicity of HER2.28ζ CAR-T cells to PD-L1+ target cells, both expressions of HER2 and PD-L1 on different cancer cell lines were detected, and PD-L1 overexpression SKOV3 cells (SKOV3PD-L1) were generated (Fig. 2c).