CD274 and chronic obstructive pulmonary disease: We performed subgroup analyses based on region (Asia vs. others), sample size of the COPD-positive group (≤70 vs. >70), treatment type (PD-1 inhibitor, PD-1/PD-L1 inhibitors, or ICIs broadly), and statistical method (univariate vs. multivariate analysis) to further evaluate the impact of comorbid COPD on survival outcomes among lung cancer patients treated with immune checkpoint inhibitors.