FOXP3 and neoplasm: One of our most striking observations was that the CD8:Foxp3 T-cell ratio was inversely correlated with PD-L1 in metastatic lesions (Figure 3), such that higher tumor PD-L1 expression was associated with a low CD8:Foxp3 ratio (p = 0.021 by t-test, and p = 0.005 by Chi square test).