Avengers: Infinity War - 13 Previous MCU Scenes It Completely Changed
9. Red Skull's "Death" - Captain America: The First Avenger

We all knew that there was more to Red Skull's disappearance at the end of Captain America: The First Avenger than was immediately obvious. He wasn't seen to die as much as he was teleported away somewhere mysterious and that meant that fans could (and did) expect to see the long-time favourite villain reappear at some point.
Even then, it felt like he would return fortified and triumphant to fight Captain America again, but the revelation that he was cursed to live as a Guardian of the Soul Stone in Infinity War changed those feeling entirely. To a certain degree, Red Skull's story is a sympathetic one (perversely so, but it's there) as death would probably have been a release for him.
And in more logistical terms for other victims of the stones, you have to now wonder whether they too have simly been trapped somewhere and could be returned. Ronin being the most notable of them, of course.