Enevhar Aldarion
Hero
It's nothing to do with the Marvel universe, but there was a show called 'The Leftovers' which is roughly this.
I've still never seen the final 3rd season, but the first two were very good.
The 4400 did something similar, as it was about the return of 4400 people, assumed missing or dead, some have been missing up to 50 years.