Cyclops is dead. As a massive fan of the character, it pains me to write that, but you have to give Charles Soule and Jeff Lemire credit for at least handling it in a pretty clever way in today's Death of X #4. The issue saw Scott Summers attempt to stop the Terrigen Mists from killing any more mutants by changing it at a molecular level, but as his conversation with Black Bolt and Medusa became more heated and he got ready to unleash an optic blast, the former obliterated him with a whisper.
Was it self defence on Black Bolt's part? Did Scott get what was coming to him? Well, it turns out that wasn't Cyclops at all. Instead, it was a psychic projection created by Emma Frost because the leader of the X-Men has actually been dead ever since he was exposed to the same Terrigen Mists which killed Multiple Man. That happened back in Death of X #1, and the Cyclops we've seen ever since has actually been Emma's doing as she wanted his death to mean something and rally the world's mutants.
So, Cyclops has become a martyr and the X-Men will soon go to war with the Inhumans as a result. However, what no one other than Alex Summers knows is that it was Emma who was responsible for all of that. A younger version of Scott is running around the place, but it seems as if it will be very hard for the version we've spent decades following to ever return. That's a massive shame and a disservice to the hero, but this is Marvel we're talking about, so that probably shouldn't come as a huge surprise.