In the movie Avengers: Infinity War, Ross Marquand played the role of Red Skull, even though Hugo Weaving played the role initially in Captain America: The First Avenger.
Why did they replace Weaving with Marquand?
Maybe because he was not interested to do it. He was pretty clear about his opinion for future portrayal of the character from very start, from his 2012's interview from collider (emphasis mine):
I [signed a multi-picture deal] for Captain America. I think the tendency, with those films, would be to probably not bring a villain back. They might for The Avengers, but I didn’t think I’d be in Captain America 2 or 3. I don’t think Red Skull will be there. And it’s not something I would want to do again. I’m glad I did it. I did sign up for a number of pictures and I suppose, contractually, I would be obliged to, if they forced me to, but they wouldn’t want to force someone to do it, if they didn’t want to. I think I’ve done my dash with that sort of film. It was good to do it and try it out, but to be honest, it’s not the sort of film I seek out and really am excited by. As an actor, to do all sorts of different films is great. It stretches you in different ways. But, I increasingly like to go back to what I used to always do, which is to get involved with projects that I really have a personal affiliation with.
But no official words came for Avengers: Infinity War specifically yet.
In an interview with Uproxx, the Russo Brothers were asked about Hugo Weaving not returning and said the following:
Did Hugo Weaving not want to do it?
Joe Russo: You know, he made a statement a couple of years back that he was done with Marvel.
It would appear they were aware of Weaving's previous statements about the role as referenced in Ankit Sharma's answer, and decided to respect his wishes not to do it again.
Because of the difficulty of the make-up process involved, Hugo Weaving refuses to reprise the role even though he had fun playing it.
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