CD4 and cancer: In the aspect of immune infiltration levels, BSG expression showed a negative correlation with nearly all six types of immune cells (B cells, CD4+ T cells, CD8+ T cells, neutrophil, macrophage, and dendritic cells) in THCA, CHOL, and SKCM (p < 0.05, Figure 7C) rather than other cancers (Supplementary Figure S5).