So far, in VSCode, we had OmniSharp powered C# extension. Although good enough to start working on basic C# projects, it lagged things like solution explorer, creating a project from templates, building/rebuilding projects, and running unit tests.
But this week, they launched C# Dev Kit, a new extension (still in preview and closed source) - which introduces many cool features:
<snip from extension’s page>
- Project System / Solution Explorer
- Solution Node Actions
- Add Project
- Build/Run Project
- Code Editing (Uses the C# extension)
- Refactoring
- Code Navigation (Go To Definition/References)
- Code Completions
- Roslyn powered semantic awareness
- Package Management
- Automatic NuGet Restore
- Testing
- Discover, Run, and Debug Tests
</snip>

Read more about it in the official blog here - https://devblogs.microsoft.com/visualstudio/announcing-csharp-dev-kit-for-visual-studio-code/
You can install it from VSCode extensions or directly from below.