Chronic airway inflammation in COPD is associated with the activation of tissue-resident (e.g., macrophages, mast cells) and -infiltrating immune cells (e.g., neutrophils, eosinophils, basophils, CD8+ T lymphocytes) in the lumen and wall of airways and parenchyma [88,98,99,100]. Here, CD8A is linked to chronic obstructive pulmonary disease.