Marvel: Immortality

Anath-Na Mut (Sphinx)
The energies of the stone also rendered Mut functionally immortal in the sense that he was immune to the effects of aging and to all known Earthly diseases and infections.

Azazel
Azazel is an extremely long-lived mutant. His aging process is greatly reduced, and he can apparently regenerate injured or missing cells from even near-fatal injuries.

Cain Marko (Juggernaut)
Juggernaut is immune to aging.

Christopher Muse (Triage
Triage has also shown signs of immortality. This was during their second encounter with the Brotherhood when he was stabbed in the neck by Raze and left for dead. He, however, managed to come back to life in a few minutes. It is yet to be confirmed if natural aging has also an affect on him, or if he is only capable of healing himself using the life-force within him.

Craig Hollis (Mister Immortal)
Mister Immortal possesses the ability to come back to life from any imaginable death that he suffers. It usually takes about ten minutes for him to completely recover. This gives him the courage to try lots of daring stunts, and so he is always willing to put his life on the line for the rest of the team. One side-effect of his ability, is that when he comes back, he becomes very angry, and it was usually up to Dinah Soar to calm him down. He also does not age or get sick, and does not need to eat, drink, or breathe. He also possessed an endless will to live.

Gabriel Shepherd (Shepherd)
Shepherd is virtually immortal, or his aging process is greatly retarded. He has been in hiding for over 600 years since his people were wiped out.

Jubilation Lee (Jubilee)
Though Jubilee isn't technically alive, she is functionally immortal for all intents and purposes. Since she isn't alive, she is immune to the effects of all known Earthly diseases and infections. As long as she feeds on fresh blood on a regular basis, Jubilee's aging process is completely halted as well.

Selene Gallio
Her aging process is greatly reduced and she can apparently regenerate injured or missing cells from even near-fatal injuries.

Shadow King
As an astral form, he can only be harmed by attacks that are able to damage such a form, such as psychically or using certain magical weapons. He has demonstrated the ability to live beyond the death of his physical body.

Wade Wilson (Deadpool)
Deadpool's healing factor provides him with an extended lifespan by slowing the effects of the aging process to an unknown degree. His lifespan is extended to such a degree, that an alternate reality version of him was alive and still in business as Deadpool 800 years in the future. Deadpool has established a relationship with the personification of Death and as a result has been cursed by Thanos to be unable to die.