In this phase I clinical trial FL-HCC patients and other cancer patients with proof of the DNAJB1-PRKACA fusion will be treated to evaluate the immunogenicity along with safety and toxicity as well as first efficacy of the DNAJB1-PRKACA fusion transcript-based peptide vaccine Fusion-VAC-XS15 combined with the immune checkpoint inhibitor atezolizumab. The gene discussed is PRKACA; the disease is hepatocellular carcinoma.