Legacy app modernization shouldn't start with a blank repo and a risky rewrite. This session shows how GitHub Copilot app modernization — GitHub's AI-powered toolset for upgrading and migrating legacy applications — helps teams analyze, plan, refactor, test, secure, and migrate .NET and Java apps across IDE and CLI workflows. You'll see a practical modernization playbook that combines GitHub Copilot app modernization, GitHub Actions, built-in security checks, and Azure-ready migration patterns. This turns a traditionally slow, high-risk effort into one that's safer, faster, and repeatable at scale. Rather than rewriting from scratch, teams assess what they have, upgrade frameworks and dependencies, remediate vulnerabilities, validate with tests, and move to the cloud with a human in the loop at each step.