Microsoft's Surface chief Panos Panay recently opened up on the WIRED's Gadget Lab podcast and talked about the Surface Go and its position in the Surface family. However, he categorically denied the possibility of a Surface Phone but did say there will be new form factors and new change in the market.
https://www.notebookcheck.net/Panos-Panay-talks-of-new-Surface-form-factors-but-don-t-get-your-hopes-high-for-a-Surface-Phone.316626.0.html