Atezolizumab plus bevacizumab combination therapy was approved worldwide for use 
in 2020. A 30% objective response rate with 8% complete response (CR) was 
achieved in a phase 3 IMbrave150 trial. Here, the change in the treatment 
strategy for hepatocellular carcinoma (HCC) using atezolizumab plus bevacizumab 
combination therapy is reviewed. The phase 3 IMbrave150 clinical trial was 
successful because of the direct antitumor effect of bevacizumab, which shifted 
the suppressive immune microenvironment to a responsive immune microenvironment, 
in addition to its synergistic effects when combined with atezolizumab. The 
analysis of CR cases was effective in patients with poor conditions, 
particularly tumor invasion in the main portal trunk (Vp4), making the 
combination therapy a breakthrough for HCC treatment. The response rate of the 
combination therapy was 44% against intermediate-stage HCC. Such a strong 
tumor-reduction effect paves the way for curative conversion (ABC conversion) 
therapy and, therefore, treatment strategies for intermediate-stage HCC may 
undergo a significant shift in the future. As these treatment strategies are 
effective in maintaining liver function, even in elderly patients, the 
transition frequency to second-line treatments could also be improved. These 
strategies may be effective against nonalcoholic steatohepatitis-related 
hepatocellular carcinoma and WNT/β-catenin mutations to a certain degree.