Growing　evidences　have　proved　that　tumors　evade　recognition　and　attack　by　the　immune　system　through　immune　escape　mechanisms,　and　PDL1/Pbrm1　genes　have　a　strong　correlation　with　poor　response　or　resistance　to　immune　checkpoint　blockade　(ICB)　therapy.　Herein,　a　multifunctional　biomimetic　nanocarrier　(siRNA-CaP@PD1-NVs)　is　developed,　which　can　not　only　enhance　the　cytotoxic　activity　of　immune　cells　by　blocking　PD1/PDL1　axis,　but　also　reduce　tumor　immune　escape　via　Pbrm1/PDL1　gene　silencing,　leading　to　a　significant　improvement　in　tumor　immunosuppressive　microenvironment.　Consequently,　the　nanocarrier　promotes　DC　cell　maturation,　enhances　the　infiltration　and　activity　of　CD8+　T　cells,　and　forms　long-term　immune　memory,　which　can　effectively　inhibit　tumor　growth　or　even　eliminate　tumors,　and　prevent　tumor　recurrence　and　metastasis.　Overall,　this　study　presents　a　powerful　strategy　for　co-delivery　of　siRNA　drugs,　immune　adjuvant,　and　immune　checkpoint　inhibitors,　and　holds　great　promise　for　improving　the　effectiveness　and　safety　of　current　immunotherapy　regimens.　A　multi-functional　biomimetic　nanocarrier　(siRNA-CaP@PD1-NVs)　is　developed,　capable　of　simultaneous　and　efficient　delivery　of　nucleic　acid　drugs　(siRNA),　immune　adjuvant　(CaP),　and　quasi　immune　checkpoint　inhibitors　(PD1-NVs).　It　can　not　only　enhance　the　cytotoxic　activity　of　immune　cells　by　blocking　PD1/PDL1　axis,　but　also　reduce　immune　escape　via　Pbrm1/PDL1　gene　silencing,　leading　to　a　significant　improvement　in　tumor　immuno-gene　therapy.　image