Anytime Mar_Vell has returned it was mainly trademark renewal.
He appeared in a story where Silver Surfer was in a realm of the dead and aided him. It was written by Starlin. Surfer told him before he left that he wished he knew Marv in his lifetime and after Surfer was gone Marv said "Perhaps in another"
Cosmic Powers Unlimited #1: Thanos is guardian of the reality gem and uses its power as a test for a larger plan. He warps reality and brings Mar-Vell back to life. Marv instantly divines via cosmic awareness what Thanos' true plan is for the gem and talks him out of it, as he knew that Thanos would want him to. He also tells Thanos that he is resolved to remain dead and Thanos respects his wish and sends him back.
Civil War: The Return: Mar-vell pulled from the past to the present. Decides to take advantage of the moment to reestablish himself as a hero and not someone known for having died in bed.
Secret Invasion: retcons/reveals that the time warped Mar-Vell is actually a skrull copy, and is hence known by angry fans as Captain Skrull-Vell. He is destroyed in the fighting.
Avengers vs X-men: the Phoenix Force is coming, is diverted to the Kree system where Kree have placed Marv's body in a space station. The phoenix power kills all the living and the station but Marv's body is rejuvenated and his spirit pulled back into it by the Phoenix power. His cancer cells were said to be in stasis, which immediately told me he was going to die again. The phoenix was going to wreck the Kree Homeworld, Marv divines that it wants the energy back that was in Marv so he willfully sacrifices himself and the energy is reclaimed.
His body soft landed on a planet and plant life began growing around him. Carol Danvers is inspired to change her name to Captain Marvel.
The writer Rick Remender hinted that may not be the last of Marv, but so far nothing has been done that I am aware of.
So he was brought back at least three times just to be re-killed each time? Seems kind of, how should I say, pointless? Trademark law sucks huh?