Cancer immunotherapy uses monoclonal antibodies or checkpoint inhibitors to assist the immune system fight malignancies. Liver cancers such as HCC and ICC escape detection through CTLA-4 and PD-1/PD-L1, but drugs like ipilimumab can block this. High CTLA-4 in ICC is linked to worse outcomes. The gene discussed is CTLA4; the disease is hepatocellular carcinoma.