“Microsoft is launching a new command line app for Windows, dubbed Windows Terminal. It’s designed to be the central location for access to environments like PowerShell, Cmd, and the Windows Subsystem for Linux (WSL). Microsoft is adding multiple tab support alongside theming and customization for developers who want to tweak the Terminal app.”

They’ve also open sourced it.
Source code: https://github.com/microsoft/Terminal

See also: https://devblogs.microsoft.com/commandline/introducing-windows-terminal/

Source: Microsoft unveils Windows Terminal, a new command line app for Windows – The Verge