KIR3DL1 and HIV infectious disease: Whether and how NKG2 receptors contribute to antigen-specific NK responses to HIV antigens in macaques; why NKG2C+ and NKG2A+ populations are associated with memory-like responses to HCMV and EBV in humans, respectively; and whether the KIR3DS1+ and KIR3DL1+ NK cells that expand during HIV infection in humans become memory cells are important and open questions in the field.