Given that the MHC-II restricted peptide cancer vaccine relies on MHC-II molecules to prime initial antigen-specific immune responses, we further combine PCSK9 inhibitors with OVA-II tool peptide vaccine in treating syngeneic B16-OVA melanoma model and proved that combinatorial treatment can achieve better anti-tumor effects than monotherapy. The gene discussed is PCSK9; the disease is neoplasm.