At Build 2019 in May, Microsoft announced Windows Terminal, a terminal application for developers who use Command Prompt, PowerShell and the Windows 10 Windows Subsystem for Linux. On June 21, a listing for the preview version of Windows Terminal appeared in the Microsoft Store. But for now, a working version is not available to the public -- at least not without a code to redeem it.
Update: Microsoft released the Windows Terminal app preview later in the day on June 21. It's available in the Microsoft Store for Windows 10 users for free for those running the Windows 10 May Update/1903 (or higher).
The Store listing (thanks to @stanzillaz for digging it up) describes Windows Terminal preview as a "very early preview release" with "many usability issues, most notably the lack of support for assistive technology."
The new open-sourced Windows Terminal app will include multiple tabs, Unicode and UTF-8 character support, a GPU accelerated text rendering engine, and custom themes, styles, and configurations, Microsoft officials have said.
Those who want to build the app themselves can use the Windows Terminal code on GitHub to do so. In the notes there, Microsoft officials said an official preview build would be available in "Mid-June."
Microsoft published the source code or Windows Terminal on GitHub alongside its existing Windows Console Host, aka conhost.exe, the original Windows command-line app. Console Host's main mission following the announcement of Windows Terminal is backwards-compatibility with existing console subsystem apps, officials have said. Windows Terminal will install and run together with Windows Console.