Blockade of HLA-E:NKG2A–mediated inhibition in vivo is a therapeutic strategy being explored through clinical trials of an antibody against NKG2A (monalizumab) for treatment of rheumatoid arthritis (NCT02331875), cancer (NCT 02557516, NCT02643550, NCT02459301, NCT02671435), and stem-cell transplantation (NCT02921685), because a role for HLA-E–mediated immunosuppression is recognized in these disorders (30, 31). Here, HLA-E is linked to cancer.