Phase 1 clinical trials with human bolus i.v. infusion IL-15 (rhIL-15) or IL-15 superagonist N-803 have demonstrated that this cytokine may induce significant expansion and/or activation of CD4+, CD8+, and NK effector cells in vivo, and therefore, it has been applied to treat cancer or viral infections such as HIV [31,32,33,34,35]. Here, CD8A is linked to cancer.