Natural killer (NK)-cell receptors (NKRs) on CD8+ T cells can modulate antigen-specific T-cell activity but their function and rules that govern their expression remain unclear. Recent work has provided new insight into CD94-NKG2A expression on T cells. Whereas upregulation on the cell surface is induced following T-cell receptor (TCR) engagement, commitment to CD94-NKG2A expression is a clonal attribute. NKRs can therefore shape cytotoxic T-lymphocyte (CTL) responses and should be considered in designing vaccine therapies.