A developer has managed to get Windows 10 on ARM to boot on his Snapdragon 835-powered Galaxy S8 and published a proof-of-concept for the same. Developer Evsio0n managed to build a barebone UEFI firmware for the Galaxy S8 using the TianoCore project to boot Windows 10 on ARM on it. Other developers are also working on bringing Windows 10 on ARM to other Snapdragon 835-powered devices like the Mi 6.
The firmware can currently boot Windows Preinstallation Environment (WinPE). Since there is no ACPI implementation whatsoever, the device cannot run a full-blown version of Windows 10.
This goes without saying but this is still a proof of concept from the developer as there is still a lot of work that needs to be done to make Windows 10 on ARM get to a daily driver level on the Galaxy S8. The source code for the UEFI firmware has been made available by the developer, so if you wish to tinker around on getting Windows 10 on ARM running on your Galaxy S8, head over to this link for instructions on how to compile the firmware. The process does require your Galaxy S8 to be rooted with TWRP recovery installed on it.
Source: XDA Developers