In the current study, we analyzed peripheral blood mononuclear cells (PBMC) from healthy CMV seropositive and hematopoietic stem cell transplant (HSCT) patients harboring active CMV infection to show greater activation, proliferation, and expansion of NKR‐P1A‒ NK cells relative to NKR‐P1A+ NK cells in CMV‐infected individuals. Here, KLRB1 is linked to cytomegalovirus infection.