The Legend of Zelda producer Eiji Aonuma confirmed that the developers are already hard at work on a new installment in the series. According to GameInformer, this information was shared through the Master Works artbook for the Breath of the Wild.
Currently, there is nothing known about the upcoming game. For all we know, the next project can be a tiny mobile game or a large title for Switch. The start of development itself is unsurprising as The Legend of Zelda is one of the best-selling series of the company and The Breath of the Wild has won the Game of the Year award.