Of note, despite that PPA1-DOX and PPA1 are expected to harbor similar targeting ability in principle, the superiority of PPA1-DOX in tumor treatment is most likely benefited from the cytotoxic effect of DOX once released into tumor tissues, demonstrating that the combination regimen of coupling PD-L1 polypeptide with DOX represents a potential targeted treatment strategy of colon cancer. Here, PPA1 is linked to neoplasm.