Not sure if this has come up previously, but Melisandre said that Azor Ahai would be reborn 'amidst salt and smoke'. Many readers seem to have taken to the idea that this person will have had at some point lived on Dragonstone.
However, At Jon's 'Death' it is said that his wound is 'smoking' and also notes that Bowen marsh was crying during the attack (salt in his tears).
Could Jon Snow be Azor Ahai reborn? I cannot see him being killed off at this point so have to assume that Melisandre will either 'raise him' or will have foreseen the attack and sent another man dressed in a 'glamour' of Jon Snow.