While we’ve already been introduced to the Kree thanks to Ronan the Accuser, the MCU hasn’t decided to pursue the Skrull story arc in the theaters yet. The Kree-Skrull War is actually a rather iconic story line in the history of the Avengers. A lot of fans that have never read the comic books probably won’t know about it, but this eight-issue story line (hey that was big time back then) was all about the Avengers finding themselves stuck in the midst of a galactic war between two races that absolutely hated one another and were set to use earth as a staging ground for their continuing conflict. The Kree and the Skrulls are intergalactic races that in the comics have been fighting for longer than humanity has existed apparently, and this entire thing was kicked off when Mar-vell, the original Captain Marvel, arrives on earth, much to the chagrin of everyone else that sees him as a sign of bad things to come. Unfortunately his arrival sparks more than just a bout of xenophobia that was worse than anything Superman had to deal with.
The Avenger’s lost a lot of face with the coming of the Kree.
Since the Avengers wouldn’t cooperating with the Alien Activities Commission that had been formed to deal with extraterrestrials, their reputation was instantly marred as the mob of people that condemned them saw fit to turn on earth’s heroes without much prompting. Unfortunately, well, maybe fortunately, a lot of this could be laid at the feet of the Skrulls, who are a race of shapechanging aliens that can alter their forms to look and even sound like others in order to commit espionage on a very catastrophic level. The Skrulls used this ability to create mass hysteria and fear among the public, thereby insuring that people would turn on the Avengers as traitors for daring to side with an alien rather than their own people. Eventually the Skrulls are found out and are either forced to flee or are cornered by the angry mobs they helped to form. In any case they lose their credibility and the Avengers’ name is restored.
Ronan the Accuser was there too.
Ronan was attempting to revert the earth to a prehistoric state that would serve as a staging ground or a base for his people in an effort to help the Kree gain an advantage over the Skrulls. Thankfully he was stopped by the Avengers, meaning that even in the comics he wasn’t quite as effective as he wanted to be. It seems fair to say that while, to the average human, Ronan might be kind of intimidating, to anyone with some power and the skills to use it with he’s kind of a joke, since the Avengers defeated him easier than they did many other villains they’ve gone up against. And do remember that Ronan was just a pawn of Thanos’ in Guardian’s of the Galaxy. He thinks he’s big and bad but in truth Ronan is kind of a bully that, when beaten, sulks and pouts like any other bad guy that can’t figure out why they lost.
A faithful recreation isn’t possible unfortunately.
This is largely because there are still characters the MCU doesn’t have access to and for the proper story line to be played out there would need to be certain characters that would have to be released. It’s also fair to say that the ideas conceived in the 70s wouldn’t be quite as feasible today since the image of one of the Avengers becoming a caveman because of an effect from a machine seems like something that fans would tear apart in a big hurry trying to debunk. After all, fans have been ripping apart sound theories for years now since the MCU got started, all while claiming to still enjoy the films. The story is still pretty great since with the emergence of the Skrulls things tend to get a lot more unbalanced considering that with these aliens put into key positions throughout the world there’s no telling who’s real and who’s an alien wearing a false form. There are stories in the comics of those Skrulls that are able to emulate powers and certain abilities, but really it seems like the Super Skrull is the only one that can really copy any kind of power, and only that of the Fantastic Four. Otherwise the Skrulls are good for dissension and possible subterfuge, but little else.
It would seem like a good idea to bring these two races into the MCU with even more force but it seems highly unlike since when Captain Marvel does come out she’s going to be featured more prominently as an origin story that takes place long before Infinity War kicks off. So the whole war might not be possible, but aspects of it could surface if the filmmakers are willing.