We used the NSGEP to the drive the expression of CRISPR-CasΦ knocking down the Cyclin-dependent kinase 5 (CDK5) gene in bladder cancer cell specifically, which would inhibited the expression of interference on regulatory factor 2 to down-regulate the expression level of PD-L1 on the surface of tumor cells [21]. Here, CDK5 is linked to urinary bladder cancer.