CD274 and neoplasm: Some studies have indicated that PD-L1 expression in tumor cells is sufficient for tumor progression,68 while others have claimed that PD-L1 expression in other tumor-associated cell types is important.69–71 Therefore, although there is a general consensus on the association of PD-L1 expression with tumor progression,72–75 many other factors influence the therapeutic outcome of classical therapies and immunotherapies.76 The role of PD-L1 in tumor progression is a very active subject of research that is outside the scope of this commentary and has been extensively reviewed elsewhere.77