HLA-E and neoplasm: Due to the immunosuppression and pro‐angiogenesis functions of tumour‐associated macrophage, we performed an in vitro experiment by isolating the macrophages (monocyte‐derived) and NK cells from human peripheral blood mononuclear cells and co‐culturing them to investigate the role of HLA‐E‐KLRC1 signalling (detailed methods were shown in the Supplementary Materials).