NECTIN2 and acute myeloid leukemia: PVR and PVRL2 are physiologically expressed on hematopoietic cells and might be further upregulated by cancer cells as a mechanism of immune escape, whereas in AML, PD-L1 is not constitutively expressed, but upregulated by treatment with hypomethylating agents or during BiTE® antibody construct therapy [26, 28–30].