It has never been particularly easy to move sessions or projects from one DAW to another. There are two interchange standards that have reasonably widespread support:
In practice both of these standards have such complex and/or incomplete specifications that different DAWs support them only partially, differently, or not at all.
To move an Ardour session to another DAW, you have 3 basic choices:
To move a session from another DAW to Ardour, you have 2 basic choices: