CD8α encodes the CD8 alpha chain of the αβT cells, proposed as a quantifiable indicator for CD8+ CTL recruitment or activity assessments and a robust biomarker for responses to anti-PD-1/PD-L1 therapy. In NK-cells, the presence of CD8A homodimers at the cell surface provides a survival mechanism allowing conjugation and lysis of multiple target cells. CD8A homodimer molecules also promote the survival and differentiation of activated lymphocytes into memory CD8 T-cells.