New in Windows Terminal 0.9: open panes within a tab from the command line.

Try:

wt -d c: ; split-pane -p "cmd" -d c: ; split-pane -p "Windows PowerShell" -d c: -H

For more info, see https://t.co/p2RvzVnWcS#Windows10#Terminal#CLIisCoolAgain#WindowsTerminal#NoGUI4Me pic.twitter.com/riMXXKfYgI

— Windows Dev Docs (@WindowsDocs) February 24, 2020