CD8A and primary biliary cholangitis: dnTGFβRII Aire−/− mice spontaneously develop severe autoimmune liver disease, exhibiting symptoms of both PBC and AIH, with CD8+ T cells as the pathogenic effector cells.[8] Herein, we report that among CD8+ T cells, the specifically expanded PD‐1+CD8+ T cells in liver is a critical pathogenic subset.