By obtaining the DEGs of different cell types between the control group and the COPD group, the results showed that among the six key CEM-DEGs, PLA2G1B was significantly downregulated in the epithelial cell category of the COPD group, which was consistent with the previous transcriptome results (Figure 8A, Supplementary Table S9). The gene discussed is PLA2G1B; the disease is chronic obstructive pulmonary disease.