PDCD1（Programmed cell death protein 1，PD1），a member of the extended CD28/CTLA-4family of T cell regulators，is involved in the regulation of T-cell function during immunity andtolerance. PD1 has two ligands, PD-L1 and PD-L2, which are members of the B7 family. PD-L1 is highly expressed in several cancers. The expression of PDL1 has been correlated with the progression and poor prognosis of certain types of human malignancies. Tumor-induced PDL1appears to utilize multiple mechanisms to facilitate the evasion of host immune surveillance, including the promotion of T cell anergy, exhaustion, unresponsiveness and apoptosis. PD1inhibitors, as a new class of drugs that block PD1, activate the immune system to attack tumors and are used to treat certain types of cancer. The coding sequence of extracellular region of PD1 was replaced with human counterpart byCRISPR/Cas9 technology on C57BL/6 background. Intracellular region of murine PD1 was completely retained and normal intracellular signal transduction was guaranteed. The expressionof hPD1 in homozygous C57B6-hPD1 mice were similar to mPD1 expression in wildtype. These mice are ideal models for anti-PD1 drug evaluation and immunotherapy drug development.