VGFacts

It has Captain Toad exploring areas of New Donk City, implying this game takes place during the events of Super Mario Odyssey, but if it's a port, we can add Nintendo Switch as one of the System Names to the Captain Toad: Treasure Tracker page.

It is probably a port with new content. That's my guess. If they say Captain Toad 2 then I'll pay (already bought it on Wii U)