Efficacy and Safety of Nivolumab Plus Ipilimumab in Patients With Advanced Hepatocellular Carcinoma Previously Treated With Sorafenib Thomas Yau , Yoon‐Koo Kang , Tae‐You Kim +18 more ClinicalTrials.gov Identifier: NCT01658878. 2020 JAMA Oncology 1129 citations