CD40 and cancer: Cancer vaccines can amplify a preexisting response by expanding tumor-specific T cell populations, broadening the T cell repertoire, and promoting the transport of T cells to tumor lesions (Figure 2c).151,152 Cancer vaccines are typically composed of soluble tumor antigens (e.g., oncoviral, oncofetal, cancer-testis, or neoantigens), formulation (e.g., peptide, nucleic acid, or whole tumor), delivery vehicle (e.g., liposome, cell-based, or viral-based), and an immune adjuvant (e.g., CD40 agonist, TLR agonist, or GM-CSF).