A recent study by Kim et al. [58] indicated that immunohistochemical analysis of GzmB in surgically removed lungs exhibiting centrilobular emphysema demonstrated that the correlation between the quantity of GzmB+ cells and FEV1% was similar to the association between the Treg cell count and FEV1% in COPD lungs, suggesting that GzmB could serve as a functional marker for Treg cells. This evidence concerns the gene GZMB and chronic obstructive pulmonary disease.