The present invention provides a method of producing a vaccine composition for the treatment of cancer comprising a fusion protein of at least two peptide sequences, the method comprising: (a) generating a library of peptide sequences； (b) obtaining at least one antibody that binds to an antigen associated with cancer or a checkpoint antigen； (c) screening the library generated in step (a) with the at least one antibody of step (b) to identify at least two peptide sequences that specifically bind to the at least one antibody； and (d) combining at least two of the peptide sequences identified in step (c) to produce a fusion protein, wherein the fusion protein, when administered to a subject, induces an antibody response directed against the antigen associated with cancer or the checkpoint antigen.
