This article contains spoilers for Wolverine #8 by Benjamin Percy and Adam Kubert.
Iron Man is figuring out the X-Men's greatest secret. Jonathan Hickman's X-Men relaunch has seen the entire mutant race gather on the living island of Krakoa. The mutant nation has been grudgingly accepted by the United Nations, granted with a little gentle psychic persuasion from Emma Frost. But the mutants are keeping a lot of secrets from the rest of the world.
The greatest secret is the fact the X-Men have conquered death, using a synergy of mutant powers and Cerebro technology to resurrect the dead. They are gradually restoring all the millions of mutants who have been slain over the decades, including the 16.5 million who died on Genosha. But it's surely only a matter of time before somebody begins to figure out that there's something strange going on.
Wolverine #8 reveals Tony Stark is beginning to work out the X-Men's greatest secret. Beast has secretly begun to spy upon some of the world's powerful figures, and one recording is clearly of Stark talking to Hellcat at his ski villa in the French Alps.
"Hey, Patsy. What do you think of this Bordeaux? You like it? I like it too. It's just that... maybe I'm crazy, but it really tastes more like a Left Bank than a Right Bank to me. Hmm. Anyway. Just to keep the crazy going for a second... I'm starting to think something screwy is going on with Krakoa. I mean beyond the whole big swinging #$%@ treaty business. I'm talking about their numbers. I've been tabulating accounts of their deaths... and comparing it with their current population, and... the math just doesn't add up."
In truth, there is simply no way the X-Men can keep their secret for much longer. The mutant race is literally expanding by millions, and mutants who are killed working for Krakoa are being resurrected again within days. Quentin Quire alone has died more than half a dozen times while operating as a member of X-Force, and it's safe to assume Mr. Sinister's Hellions will fare much better - as Sinister has already killed them himself once in order to conceal his activities from the X-Men's own Quiet Council. People are going to start working out the truth.
The interesting question is just how the world will react to the knowledge mutants have become immortal. The X-Men's conquest of death has had pronounced metaphysical effects on the nature of reality itself, with the avatar of death itself - Thanos' beloved Lady Death - almost killed by it. The Resurrection Protocols mean the mutant population will forever expand, for the citizens of Krakoa will be untouched by mortality, and questions of the sustainability of resources in the face of an ever-increasing mutant population will rear their head. This is dangerous knowledge, and while Iron Man is hardly going to start a war over the Resurrection Protocols, Beast will no doubt be concerned that others will be beginning to notice the discrepancies as well.