The Official Donnie Yen Instagram has shown three helmets, probably from Star Wars: Rogue One:
A couple of guesses:
The black helmet could be the “Shadow Troopers” official look, giving them a little more design than just painting a stormtrooper helmet black (which also evokes the Republic Commando look a bit too). The middle helmet is our standard-issue stormtrooper. The helmet on the far right could be the bounty hunter helmet or a rebel helmet of some kind (it looks very used).
Pretty neat reveal if this is indeed from Rogue One: A Star Wars Story.