In first place, it has been observed that different assays yield discordant results; additionally, PD-L1 has been recognized to have a heterogeneous expression within the same tumor, associated with variable and not completely understood immune mechanisms; third, and most important, a beneficial effect of anti-PD1 compounds was seen, in most studies, also in patients without detectable PD-L1 expression [5,6,7,8]. This evidence concerns the gene CD274 and neoplasm.