There are several different types of trailers when it comes to movies and gaming, and for those who do not know, this is what you call an 'Announcement Trailer'. It is similar to a teaser trailer, and in some cases, they are one in the same, but this simply exists to let us, the fans, know there is a new movie on its way in the near future. Usually, with a teaser or Announcement trailer like this, we are usually a year away from the film being in the cinema, but depending on when they want to release, I can bet the summer of 2026.
This announcement shows Mario sleeping under a tree as we follow a butterfly flying in the world. We get to see the underground creatures seen in the games (I believe they are from a game, but I cannot remember which one - the original Mario Kart, I think), and we get to see the infamous fish that always jump up to bite you. And consider where we see the castle in the background, and we follow the butter, there is some teleportation because the princess's castle is a lot closer to the lake. We see some toad characters, and the butterfly flies into space, and a star comes shooting down with a "Let's go!" Yeah, let's go! But I'll wait while they prep to go...until they release the next trailer. Sidestep, isn't the music a different-sounding version of the music in Super Mario World? I've not played Galaxy, so I have no idea.