CD4 and neoplasm: Conversely, spatial features that were negatively correlated with PC1 (Pearson correlation coefficient < −0.85) and thus enriched in HPV-negative tumors were characterized by increased interactions between stromal components (fibroblasts, endothelial cells, and PPSCs) and immunosuppressive cell types, including PD-L1+ macrophages and CD4+ Tregs, within the tumor stroma (Fig. 6E; Suppl.