CD8A and neoplasm: The Pearson correlation coefficient analysis showed that serum CD4 levels were correlated with CD4+T cell infiltration in the tumor microenvironment (correlation coefficient = −0.209, P < 0.005, Figure 4(a)), but CD8 and CD19 did not show this trend (correlation coefficient = −0.088, P = 0.197, Figure 4(b); correlation coefficient = −0.101, P = 0.138, Figure 4(c)).