CD8 is crucial for identifying cytotoxic T cells, playing an integral role in the immune response by interacting with Class I MHC molecules. It is particularly important in diagnostics and research for assessing immune cell populations and identifying T-cell lymphomas or other hematologic malignancies.

Immunohistochemical detection of CD8 is valuable for distinguishing between reactive and neoplastic T-cells in both research and diagnostic settings, aiding in the characterization of immune responses and lymphoid malignancies.