Rumors of such have been flying for two years (maybe more). Microsoft is no longer interested in building smartphones as it once was, but a dual-display form factor could be in the cards.
Source: Microsoft (via USPTO)
"An example implementation provides a computing a device including a first computing device portion having one or more electrical components, a first side, a second side, an electromagnetic coil, and a first metal frame having a first through-slot," the abstract reads.
The abstract goes on to explain there being a second computing device portion with one or more other electrical components, along with a mechanical joint, and other high-level details on the overall assembly. Accompanying images show a device open and laying flat, and folding onto itself.
"A mechanical joint connects the first computing device portion and the second computing device portion such that the first side is positioned to face the third side and the electromagnetic coil overlaps the first through-slot and the second through-slot along an axis running orthogonal to the first computing device portion and the second computing device portion. Control circuitry adjusts matching to compensate different physical configurations, and firmware switches the radio frequency configuration," the patent states.
Microsoft actually filed the patent nearly two years ago, in February 2018. It's hard to tell what might have changed since then, both in how Microsoft might approach a folding PC concept, and whether it is still (or ever truly was) interested in such a thing.