In the old and new editors, you can create a Confluence task by using the brackets together [] which is a nice shortcut.
On the old editor, pressing the tab key would indent the task to make it a "subtask" of the task above. This does nothing on the new editor.
I've also submitted a support request for this and if it turns into a CONFCLOUD issue, I'll post that here so anyone else who wants this feature to carry over, you can add your vote.