CD8A and neoplasm: The shortcomings of prior vaccines may be in part due to weak immunogenicity of the vaccine leading to insufficient magnitude of CD8+ T-cell responses; inadequate, or loss, of expression of the tumor antigen, thereby enabling tumor cells to evade recognition; and/or, inability of vaccine-induced T cells to overcome the suppressive tumor microenvironment.15,20,148 Recent advances in tumor antigen identification and selection algorithms are enabling more reliable antigen selection, and checkpoint inhibitors have proven effective for unleashing T cells to mediate tumor-specific killing.