CD274 and neoplasm: Our results are in line with recent papers reporting: (i) an increase, in several tumors, of infiltrating NK cells expressing PD1 as compared with circulating NK cells [23,66,67], (ii) the existence within WT tumors of an immune-engaged tumor microenvironment, characterized by infiltrating NK cells [38], and (iii) an elevated frequency of PD-L1 positive tumor cells in WT biopsies, predominantly in the blastema [65].