Nature, Published online: 19 February 2025; doi:10.1038/s41586-024-08508-4In a phase 1 trial, patients with pancreatic ductal adenocarcinoma who were treated with surgery and bespoke neoantigen mRNA vaccines combined with anti-PD-L1 and chemotherapy exhibited marked long-lived persistence of neoantigen-specific CD8+ T cell clones, which correlated with prolonged recurrence-free survival at a 3.2-year follow-up.