Based on their immune-activating mechanisms, ACPs can be categorized into two main groups: targeted peptides that inhibit immune-related signal pathways aberrant in cancer cells such as PD-1/PD-L1 interaction, cGAS-STING pathway, and CD47/SIRPα; and lytic peptides, which form pores in cancer cell membranes to induce cell necrosis or apoptosis, and the cell fragments can act as tumor antigens to trigger the immune response. Here, PDCD1 is linked to neoplasm.