This storyline is already confirmed to be appearing in the MCU. Nick Fury, played by good ol’ Samuel L. Jackson, will be getting his own Disney+ series called Secret Invasion. In the comics, the story occurs after the Kree-Skrull War. After the war ends, a group called the Illuminati (Professor X, Namor, Black Bolt, Reed Richards, Iron Man, and Doctor Strange) get together to attack and warn the Skrulls to never use Earth in their battles again. Instead, they are kidnapped and experimented on until they finally escape.
Long story short, the Skrulls use what they learn by experimenting on the Illuminati to infiltrate Earth and mimic the heroes. They end up replacing several prominent heroes, such as Spider-Woman, Hawkeye, Elektra, and Captain Marvel (a different one). It’s yet to be seen how far the Disney+ show will incorporate this storyline. However, I’m sure someone who is “dead” (like Black Widow maybe) isn’t really dead… Who could the Skrulls be?!