CD274 and neoplasm: ICIs act by blocking the activation of tumor-induced inhibitory pathways: the first one (anti-CTLA-4) mostly at the early stage of naïve T-cell activation, at the site of antigen presentation in lymph nodes, and the latter (anti-PD-1/PD-L1) at the advanced stage of a T-cell immune response, directly in the tumor microenvironment (TME) (3), as depicted in Figure 1.