I mean, Marvel seems to be down for it. The problem is on Capcom's end, not just from a financial standpoint, but also from the standpoint of if they're willing to go along with Marvel's current wishes for their side of the roster to do it (which may piss off the FGC). Also, wouldn't Capcom USA be the ones doing the negotiations with Marvel Entertainment, since it's that side of Capcom that seems to be covering the fighting game side of things for the company (aside from development, of course)?
But if it is happening & coming out in 2019, it would make for a super-hype EVO 2017 announcement.