This Wednesday, Nintendo has a Fire Emblem Direct scheduled for launch. Nintendo of Japan has already revealed that the Direct will involve the planned Fire Emblem mobile game and many expect more details about the recently-announced Fire Emblem Warriors musou for Nintendo Switch. There's also the hope that Intelligent Systems might have a new Fire Emblem to announce for the Switch.
If you head to the official Nintendo website, look at the entry for Fire Emblem Warriors, view source code, and search for "Fire Emblem Fates", you'll find links to entries for the recent Fire Emblem titles. While the image alt text for Birthright and Conquest correctly list those games for 3DS, the Revelations alt text says "Fire Emblem Fates: Revelation for Nintendo Switch". This is leading many to believe a Revelations port is headed to Nintendo's platform. The information was found by NeoGAF user Mr. Pointy.
Revelations was the third campaign for Fire Emblem Fates, released as DLC for Fire Emblem Fates: Birthright and Conquest. The hope here is that this new Revelations is a complete package of all three campaigns, much like the Fire Emblem Fates: Special Edition that was available for 3DS.
This makes a little more sense than a new Fire Emblem for Switch. Fire Emblem Awakening was announced in September 2011, with a release in April 2012. Fire Emblem Fates was announced in January 2015, with a release in June 2015. Given a similar timetable of three years, a new Fire Emblem would likely be ready for the Switch in early to mid-2018, not this year. Sure, Intelligent Systems could be rushing, but even money is on bolstering Switch's future schedule.
This could just be an webcode error though. We'll see on Wednesday, January 18, at 2PM PST/5PM EST.