Does a token that leaves the battlefield and returns count as the same permanent for aura attachment?

Tokens are permanents while they are on the battlefield, but the moment a token leaves the battlefield it ceases to exist — it is simply gone. This is governed by CR 111.7, which states that a token that has left the battlefield can't move to another zone and doesn't exist anywhere else.

Even setting aside the token-specific rule, any permanent that leaves the battlefield and comes back is treated as an entirely new object with no connection to its previous existence (CR 400.7). This means Auras, Equipment, and counters that were attached to the old object have no automatic relationship to the new one.

If an effect says 'return that permanent to the battlefield,' it creates or moves an object that the game considers brand-new. Any Aura that was attached to the old permanent falls off when that permanent left (the Aura's enchanted object is gone), and the Aura doesn't automatically re-attach to the 'returned' permanent. The Aura would instead go to the graveyard unless a specific effect says otherwise (CR 303.4c).

Concrete example: You control a 1/1 Saproling token with a Rancor attached to it. Your opponent casts Unsummon targeting the token. The token leaves the battlefield and ceases to exist (CR 111.7). Rancor's own text returns it to your hand — because there is no permanent it's enchanting anymore (CR 303.4c triggers). There is no token to 'return,' and even if there were, it would be a new object with no memory of having Rancor attached.

In short: tokens don't return from anywhere once they leave the battlefield, and even for non-token permanents, leaving and re-entering always creates a new game object that starts fresh with respect to attached Auras and other dependencies.