B6-hPD-1/hPDL1 mice are PD-1 and CD274 double humanized mouse models obtained by mating PD-1 humanized mouse models with CD274 humanized mouse models. They express human PD-1 and CD274 genomic sequences under the control of mouse promoters. This model is a valuable tool for studying cancer immunotherapy. In addition, this model also provides a powerful preclinical research platform for evaluating the efficacy and mechanism of therapeutic drugs targeting PD-1 and PD-L1.