Five‑year follow‑up shows the investigational Merck and Moderna therapeutic cancer vaccine maintained a 49% reduction in risk of recurrence or death when added to Merck’s anti‑PD‑1 therapy, Keytruda, in melanoma patients. The durability of benefit strengthens the companies’ case as they advance pivotal work and regulatory strategy, and investors and partners are reassessing the vaccine’s commercial potential. The sustained hazard reduction supports plans to close out later‑stage programs and informs trial design for confirmatory studies.