CD8A and hepatocellular carcinoma: Therefore, we further investigated cytotoxic lymphocytes (CD8+ T cells and natural killer [NK] cells) in human HCC tissues, and the number of cytotoxic lymphocytes significantly reduced in HBV‐infected HCC tissues, which expressed BMP9 at lower levels, compared with HBV‐uninfected HCC tissues (Figure 3C,D).