We found that the proportion of PD-L1+ cDC1 was significantly lower in the patients with COPD with rapid lung function decline compared with those without a rapid decline in lung function (4.6 ± 4.7% vs. 15.5 ± 18.6%, respectively; p = 0.02, Figure 2A). Here, CD274 is linked to chronic obstructive pulmonary disease.