CD40 and neoplasm: CD40L, mainly expressed by Th cells, activates DCs via CD40; thus, they are optimally equipped to prime cytotoxic T lymphocytes (CTLs), providing them with “a license to kill.”106 CD40 agonists mimic this interaction, promoting DC maturation by upregulating MHC molecules, co-stimulatory molecules (e.g., CD80/CD86), and IL-12 production, fueling the expansion of tumor-specific CTLs.107