The one thing that all comic book fans have gotten used to is that dead superheroes and supervillains never stay dead. There is always a way for dead characters to end up resurrected. However, in the movies, that is not true for the MCU outside of rare occurrences. WandaVision looks to present a way to bring back at least one dead character.
With that said, most characters in the MCU movies who died are not coming back. Even the most popular character from the entire movie franchise died, and Robert Downey Jr. emphasizes it won't change, and he won't be back. With that in mind, many dead MCU characters are still alive and kicking in the comics.
10 Iron Man
In one of the most shocking moments in the MCU, Iron Man sacrificed himself to save the world in Avengers: Endgame. In an even more shocking moment, in a world where superheroes never stay dead, Robert Downey Jr. said he is not returning to the role in the future.
However, while Iron Man is now dead in the movies, he is still alive and well in the comics. Stark did die in the comics, but he has a new cloned body, and his consciousness was transferred into it, and he is still fighting to save the world in his own monthly title.
9 Black Widow
There is a Black Widow movie coming out in 2021, but in the MCU's real timeline, Natasha is dead. Black Widow gave her own life to earn the Soul Stone. Hawkeye tried to take his own life, as he had fallen hard thanks to taking on the role of Ronin and killing so many people.
However, Natasha wouldn't allow it, and she died to get the Soul Stone to help The Avengers beat Thanos. In the comics, Black Widow still has her own solo series running right now and is also appearing in the new Taskmaster comics.
8 Quicksilver
Quicksilver is a Marvel character that appeared in both the MCU and the Fox X-Men world. While the X-Men version (Evan Peters) is the fan-favorite and lived to the end of that franchise, the MCU version died in Avengers: Age of Ultron.
Aaron Taylor-Johnson played Quicksilver in the movie, entering the MCU with his sister, Scarlet Witch. Quicksilver died in an act of selfless sacrifice in that movie. The upcoming WandaVision has Scarlet Witch bringing back Vision from the dead, and one wonders if she brings back her brother as well.
7 Crossbones
One thing that comic book movies have always liked to do is kill the villains in the end. This happened from the early days when Joker died in Batman and continued with Doctor Octopus dying in Spider-Man 2. The MCU does this occasionally as well and killed off Crossbones.
Brock Lumlow in the MCU was a S.H.I.E.L.D. Agent who was actually a HYDRA agent who infiltrated the organization. He suffered great injuries in Captain America: Winter Soldier. After that, he became Crossbones and died in a battle with Captain America and Scarlet Witch in Captain America: Civil War. He is still alive and active in the comics.
6 Warriors Three
The Warriors Three were strong allies of Thor in his movies, including a huge role in the battle on Earth in the first Thor movie. That made their deaths so poorly done in the movies. In Thor: Ragnarok, Hela showed up in Asgard and killed Volstagg and Fandral instantly, the two men having no chance to defend themselves.
Hogun fought hard but died as well. In the comics, Fandral and Hogun are still alive and part of Warriors Three. Volstagg is still alive but is no longer a member of the team.
5 Killmonger
Killmonger might be the second greatest villain in MCU history, behind only Loki. However, in comic book movie tradition, he died at the end of Black Panther. The death was a tragic one as Black Panther took him up to see the Wakandan sunset one last time, and Killmonger asked Panther not to save him because he refused to live locked up for the rest of his life.
In the comics, Killmonger died as well — more than once. However, as with most comic characters, no one stays dead, and he was resurrected and alive again.
4 Klaw
Ulysses Klaue first appeared in Avengers: Age of Ultron as a villain working on supplying Ulton with his weapons. This is where he lost his hand, but he escaped the battle alive. Klaw returned in Black Panther, and he was one of the highlights of the movie with Andy Serkis created an entertaining villain.
However, just as viewers were falling in love with him, Killmonger killed him when he betrayed his cohort. In the comics, it appeared that Klaw died as well, but his consciousness survived through the sound wall, and he eventually was able to reform in his physical body as well.
3 Odin
In Thor: The Dark World, the twist at the end was that Loki had replaced Odin on the throne in Asgard, and there was no telling where the All-Father went. In Thor: Ragnarok, it turned out that Loki put him in a retirement home on Earth and had clouded his memories.
When Loki and Thor found him, Odin finally died and moved on to join his beloved Frigga on the other side. In the comics, Odin gave Thor the throne, but he and Frigga are both still alive.
2 Ego
In Guardians of the Galaxy Vol. 2, the MCU brought the unique and strange character Ego to the big screen. While the comics have Ego as a giant living planet, the MCU had him appear as a human (Kurt Russell) and had him as the father of Peter Quill.
By the end, the Guardians beat Ego and killed him. However, in the comics, not only is Ego not Peter Quill's dad, but he is also not dead, and some wonder if he can ever really die in the comic version of the character.
1 Ultron
Ultron was the big bad in Avengers: Age of Ultron. In the movie, Tony Stark created Ultron and watched it gain sentience and decide it needed to save the world by destroying humanity. Ultron turning evil was the same in the comics, but in the books, it was Hank Pym who created him.
However, the other difference is that the MCU had him exist due to an Infinity Stone, and he was destroyed. In the comics, it had nothing to do with that, and he has returned repeatedly over the years.