Why .net Core framework already we have .net framework which is a very mature and rich framework and lot of third party .Net libraries,NuGet Packages but works only on windows OS platform.If you want to run .net application on Cross platforms(Windows, Linux and macOS) then you can use .Net Core framework.Net core framework advantages over the traditional .net framework.
- Cross platform Support
- Micro services
- High performance
- Side by side of .NET versions per application level.
Below are the link which give detail information about the .Net Core