CD4 and cancer: We categorized the immune microenvironment into three groups based on the densities of immune cells, either CD4+ T cells or CD8+ T cells, in cancer cell nests and stromal regions: immune inflamed, high cell density in both cancer cell nests and stromal regions; immune excluded, low cell density in cancer cell nests and high cell density in stromal regions; and immune desert, low cell densities in both cancer cell nests and stromal regions (Additional file 1: Fig. S3 A to C).