CD4 and neoplasm: Tumor vaccines refer to the use of carriers such as peptides, nucleic acids, adenoviruses, or dendritic cells (DCs) to deliver tumor-associated antigens or neoantigens, combined with immune adjuvants or innate immune activation signals, to activate and expand antigen-specific CD8+ cytotoxic T cells and CD4+ helper T cells (as well as associated B cells and memory immunity).