CD274 and atherosclerosis: This, however, requires cell to cell interactions—i.e., a firm contact between the ECs and the T cells is involved, where a PD-L1 blockade, but not PD-L2, could revert the effector function responses of CD8+ T cells, by secreting IFN-γ [63], in response to the antigens presented by the endothelium, which could be regarded as an early step in the pathogenesis of atherosclerosis [77,78].