It’s pretty clear he didn’t die at the end of the first CA movie and it sure looks like he got shot into space so I think the Red Skull will be the secondary bad guy in Infinity War. He will be the Darth Vader to Thanos’ emperor (i.e. the bad guy who actually gets his hands dirty and takes an active role fighting the good guys).
I’m also positive a main character Avenger dies at the end. Leaning towards Captain America but could see it be Iron Man too.