Furthermore, the quantity of CK−/PD-L1+ CTCs was significant to stage (p = 0.0073, 95% CI –2.587 to −0.4070) (Figure 4D) and metastasis (p = 0.001, 95% CI –2.842 to −0.7325) (Figure 4E), but not to cancer subtype (p = 0.9128, 95% CI –1.276 to 1.141) at lung cancer blood samples (Figure 4F). Here, CD274 is linked to lung cancer.