PCSK9 (proprotein convertase subtilisin/kexin type 9) is a key protein regulating cholesterol metabolism. Inhibiting PCSK9 represents an effective approach to enhance the efficacy of immune checkpoint inhibitors, and combination therapy strategies involving "PCSK9 inhibitors plus immune checkpoint inhibitors" have demonstrated promising therapeutic outcomes in cancer immunotherapy experiments. Targeting PCSK9 to develop novel inhibitors or gene therapies shows bright prospects in both cardiovascular disease treatment and tumor immunotherapy. The hPCSK9 humanized mouse serves as an important model for developing PCSK9 inhibitors or gene therapies. The C57BL/6N-hPCSK9 humanized mouse model, independently developed by Mingxun Biotechnology, utilizes the genomic sequence corresponding to the human PCSK9 transcript NM_174936.4 (from 5'UTR to 3'UTR) to precisely replace the genomic sequence corresponding to the mouse PCSK9 transcript NM_153565.2 (from 5'UTR to 3'UTR). This design ensures the specific expression of the human PCSK9 gene in mice, providing a valuable experimental model for studying PCSK9-related mechanisms in cholesterol metabolism and associated diseases.