CTSS and neoplasm: The precise delivery of antigens and adjuvants to APCs in vivo through delivery vehicles is critical for specific antitumor immune responses by tumor vaccines.[10] To ensure simultaneous delivery of both antigen epitope and peptide FK‐13, we first synthesized a fusion peptide by putting these peptides in the same chain, linked by cathepsin degradable linkers reported in the previous study.[23] Specifically, we used the MHC‐I epitope OVA257‐264 (SIINFEKL) from OVA as a model antigen.