The overall survival of cancer patients is correlated with type and level of leucocyte subpopulations in the tumour parenchyma, with good survival associated with CD8+ T cells, NKs, and DCs, and poor survival associated with neutrophils, Tregs, etc. Thus, efficient admission to these well-defined leucocyte subpopulations presents conspicuous value in research as well as in clinical applications [122,123]. Here, CD8A is linked to cancer.