.NET Core 3.0 includes performance improvements, enhancements to SignalR, new endpoint routing for web apps, the introduction of Blazor and Razor Components, an in-box JSON reader, support for async streams, new C# 8.0 features, improvements to Entity Framework 3.0, support for HTTP/2, and the ability to publish self-contained executables. The presentation provides an overview of the key new features in .NET Core 3.0 across areas like performance, web development, client-side frameworks, languages, and tools.