The correlation heatmap reveals that CST2 is closely associated with various immune cells in pan-cancer, including cancer-associated fibroblasts (CAF), endothelial cells, hematopoietic stem cells, regulatory T cells (Tregs), B cells, macrophages, monocytes, myeloid dendritic cells, and CD8+ T cells (Figures 5A, B). This evidence concerns the gene CD8A and cancer.