CD274 and neoplasm: In Keynote -001 trialpatients affected by metastatic melanoma with different grade of PD-L1 expression andtreated with pembrolizumab showed a variable reduction in tumor dimention, with rengefrom 35% to 86%: even if it seems that lower PD-L1 expression correlate with lowerresponse, the high rate of response doesn’t allow to prevent this group ofpatients from immunocheckpoints treatment.