KLRK1 and pancreatic ductal adenocarcinoma: In an orthotopic implantation model for syngeneic pancreatic ductal adenocarcinoma (PDAC) tissue slices which maintains the immunosuppressive microenvironment, NKG2D CAR (chimeric NKG2D full length and CD3ζ)-T cells successfully eliminate myeloid derived suppressor cells (MDSC) and enhance the antitumor activity of subsequently infused CAR-T cells against primary PDAC cells (29).