Monolith Soft announced that it was part of the development team for The Legend of Zelda: Tears of the Kingdom. Specifically, it worked on the game design, programming, and graphics. Monolith Soft is a video game development studio that became part of Nintendo in 2007.
Though Monolith Soft was not the sole developer for Tears of the Kingdom, it worked on the game in a supporting capacity. This is what it also did with Skyward Sword, A Link Between Worlds, and the prequel game Breath of the Wild. Monolith Soft is a studio that used to work alongside Bandai Namco before Nintendo bought it in 2007. Non-The Legend of Zelda titles the studio has developed in the past include the Xenosaga series, the Xenoblade series, and the Project X Zone games.
As mentioned earlier, Monolith Soft helped to develop Breath of the Wild. Both Breath of the WIld and Tears of the Kingdom are open-world adventures in which Link roughs it out in Hyrule in order to defeat the evil spreading across the land. He can use various gadgets and tools to help him on the journey. The prequel also introduced the cooking mechanic, which Tears of the Kingdom also has.
We can find The Legend of Zelda: Tears of the Kingdom on the Nintendo Switch now.