At this point, is there any Game of Thrones fan that isn't yet convinced that Jon Snow is coming back?
WARNING: HERE THERE BE SPOILERS!
Seriously, this could end up being a fairly major plot point, so if you don't want to have anything spoiled for you, click away.
The battle being filmed was supposedly epic and featured quite a few warring factions: the Boltons, the Umbers, Wildlings, and others.
More importantly, Kit Harington was spotted in Belfast along with Iwan Rheon, preparing to film.
So if Jon Snow did indeed survive (or, more likely, was resurrected by Melisandre), does this mean he is now free of his oath to the Night's Watch and can do as he pleases? If that's the case, then he may be involved in the fight against the Boltons now that he's free to seek vengeance on them for what they did to the Starks.
At this point, the evidence is mounting that while Jon Snow was most certainly dead, he's not dead forever - and, in many ways, death might have actually freed him to grow into the man he was meant to be.
Game of Thrones Season 6 premieres in April of 2016.