CD8A and neoplasm: In the tumor-infiltrating lymphocytes (TILs), the BTLAlow CD8+ TIL subpopulation grows faster than the BTLAhigh CD8+ TIL subpopulation, but BTLAhigh CD8+ TILs display improved survival following the killing of a tumor target and heightened “serial killing” capacity, and the gene expression profile is associated with T-cell tolerance [15,16,25].