This weeks card of the week comes from my fellow librarian Coatsy.
Your opponents want to remove your commander or key combo piece just as much as you want to keep it on the field, which is why you need to be able to protect them. Gift of Immortality is an Enchantment for 2W that enchants a creature, and when that creature dies return it to the battlefield. Not only does it provide protection for a creature but it is also difficult for opponents to interact with because they would need to use multiple removal spells, or exile the creature.
The major upside of Gift of Immortality is that it returns itself to the battlefield and the beginning of the next end step attached to the same creature, this extends the amount of protection that it offers the creature. It also provides additional functionality as it can also be used to repeatedly trigger ETB or death triggers from creatures.
Gift of Immortality would be good in a wide variety of decks including: Ruhan of the Fomori; Elenda, the Dusk Rose; Roon of the Hidden Real; Zur The Enchanter; Tuvasa the Sunlit; Alela, Artful Provocateur; Brago, King Eternal