Tokyo Mirage Sessions #FE wasn't exactly a straight crossover between Nintendo and Atlus' popular RPG series. It was more of a remix title, borrowing characters from both franchises (like Chrom and Caeda) and placing them in a modern day Tokyo plagued by evil spirits called "Mirages" that feed off human creative energy. Our team of heroes consisted of aspiring and established idols based out of a talent agency. There were music videos. It was weird, but also beloved by a few members of the Engadget team.
The Switch release is called Tokyo Mirage Sessions #FE Encore, which should tell you this isn't just a straight port. It'll include a new song, new story elements and new playable characters like Tiki. It's out January 17th, and you can preorder it today.