CD44 and cryptogenic organizing pneumonia: Clusters #22393 (12.0 ± 4.9% vs. 1.0 ± 0.4%) and #22399 (20.9 ± 5.1% vs. 4.7 ± 2.0%), which were also prevalent in COP, consisted of CD8+ CD16+ CD44+ PD-L1+ T cells (Figure 4B,C).