.NET Core 3.0 introduces significant updates including C# 8.0 features, improved APIs, single-file executables, and support for new platforms like Raspberry Pi and ARM64. The release schedule for .NET shows a commitment to long-term support, with .NET Core 3.1 as the latest long-term supported version and .NET 5.0 planned for November 2020. Key enhancements also include better JSON handling, HTTP/2 support, and various .NET Standard improvements.