We found that the HHLA2 expression was significantly linked with lots of infiltrating immune cells: B cells in 20 types of cancer, CD4+ T cells in 12 types of cancer, CD8+ T cells in 13 types of cancer, macrophages in 13 types of cancer, neutrophils in 12 types of cancer, and DCs in 15 types of cancer (Figure 9). The gene discussed is HHLA2; the disease is cancer.