Sauron lives?

[Elrian]

Sauron can't come back. Despite the fact that the Silmariallin mentions that he suffers the same fate as Morgoth, imprisoned in the void until the end of days.

Sauron was not cast into the void in the Silmarillion:

Then Sauron failed, and he was utterly vanquished (conquered, defeated) and passed away like a shadow of malice.

He lost the ability to take form again, or rise in power after the ring was destroyed, but he was not cast into the void.