Nintendo recently released The Legend of Zelda: Breath of the Wild Master Works, the official artbook of Breath of the Wild. The book features art from different stages of development that Breath of the Wild went through. These sometimes come with notes from the dev team to give further context to the pieces of in-progress art. One of those notes states that Eiji Aonuma and his crack team of Zelda developers have already begun work on the next Legend of Zelda title.
With The Legend of Zelda being one of Nintendo's tent pole franchises, it's not surprising to learn that the next Zelda is already in the works. Just don't think that we will be seeing it anytime soon - Breath of the Wild released this year, six years after Skyward Sword. It wasn't even until 2013 that we saw the first hints of what Breath of the Wild would even become. Expect the next Zelda title to surface sometime in 2019 or 2020.
Meanwhile, it seems like Nintendo is also hard at work on new handheld Zelda titles with a separate team working on those entries in the series. The possibility remains open that those new handheld Zeldas could appear on the Switch, too.
Where would you like to see The Legend of Zelda series go in the future?