CD4 and neoplasm: In accordance with the earlier description, the process of classical cross-priming involves presentation of tumour-derived neoantigens by MHC class II on DCs to CD4+ T helper cells, which in turn ‘license′ the DCs through CD40 ligand (CD40L) and CD40 interactions for cross-priming and facilitate the release of cytokines IL-12 and IFNγ [33] (Figure 1).