The second player does not control a second Toad, but instead helps the first player in various ways.
A second player can join in on Captain Toad either with another controller or simply by handing off one of the Joy-Cons, whether you're in front of a TV or out and about.
On the Wii U version, Captain Toad was a solo experience, but no longer. Fortunately, the Super Mario Odyssey levels are far more interesting. If you loved those games in the Wii U version, you can't play them on the Switch. This is, sadly, at a loss of old levels previously based on Super Mario 3D World. We already know the Captain went to New Donk in Odyssey, so now we get to see the city from his adorable perspective. These new stages are based on locations in Super Mario Odyssey, such as New Donk City. First, it includes even more levels than the original game. As with most other Nintendo Switch ports, Captain Toad: Treasure Tracker boasts some special features to make it more appealing beyond sheer desire for portability.