 This is a single-arm phase II trial of Pembrolizumab Keytruda in patients with advanced, unresectable hepatocellular carcinoma. The primary objective is to assess its therapeutic efficacy in patients with unresectable hepatocellular carcinoma HCC. The primary endpoint is disease-control rate DCR defined as the proportion of patients achieving a best overall response of either a complete response CR, partial response PR or stable disease SD that is maintained for at least 8 weeks. 