This session from AWS re:Invent 2023 focuses on lessons learned from large-scale migrations and modernizations to AWS. Jonathan Allen and Oscar Rodriguez share insights on establishing the business case, setting up teams, leveraging AWS tools and services, and modernizing applications during migration. They cover key topics like executive alignment, Cloud Centers of Excellence, re-skilling, data migration, and application assessment. The presenters emphasize the importance of having a clear 'why' for migration, getting leadership buy-in, and balancing governance and agility. They also discuss AWS services like Migration Evaluator, Database Migration Service, and Application Migration Service that can accelerate the journey. Overall, the session provides a comprehensive overview of best practices for enterprises undertaking major cloud transformations.