If anyone at Marvel Studios decides that this is something worth pursuing, then there would be a few possible directions in which to take Wesely Snipes as Blade. One option would be to retroactively classify the three previous Blade films (or at least one of them), as canon in the greater Marvel Cinematic Universe. However, another option would be to just cast him as a new incarnation of the same character and not even mention the earlier years of his run as Blade. That may seem bizarre, but it's worth mentioning that the X-Men universe did that with Ryan Reynolds' Deadpool -- even poking fun at X-Men Origins: Wolverine -- and the James Bond franchise did the same thing by keeping Judi Dench around as M in Casino Royale.