After intravenous injection of P-aPDL1 into the mice, which had taken the surgery to remove B16 melanomas and triple-negative mammary carcinomas, the P-aPDL1 exhibited longer circulation time in the bloodstream; and aPDL1 would be effectively released at the surgical site through platelet activation and followed by blocking PDL1 on tumor and antigen-presenting cells (APCs) to achieve excellent efficacy for cancer recurrence and metastasis post-surgery. Here, CD274 is linked to neoplasm.