CD274 and chronic obstructive pulmonary disease: A recent study by Polverino and coworkers analysing PD-L1 expression in several cell types of lung structure and inflammatory cells from two cohorts of COPD and NSCLC patients demonstrated that both NSCLC patients and patients with a mild stage of COPD expressed the highest levels of PD-L1 in alveoli, bronchioles, and vessels compared to patients with severe COPD stages [19], further corroborating the existence of a strong link between the two pathological conditions.