Chapter 307:
If Orochimaru wanted immortality, he had many methods.
From the Living Corpse Reincarnation to the Cursed Seal of Heaven, and even Kaguya's genes, he could choose whichever path he preferred.
As for resurrection? Orochimaru also had countless approaches.
Leaving aside lesser-known methods, even the well-documented ones would suffice.
First was the Reanimation Jutsu.
However, this wasn't true resurrection. The souls summoned were bound to the caster's will, making it more of a summoning technique than genuine revival. It was a method to call a soul back temporarily, not to restore life.
The second was the One's Own Life Reincarnation developed by Chiyo of the Hidden Sand Village.
But that technique had its own severe limitations.
Not only was it hard to obtain, but it also required a life to be exchanged for another. Most critically, it required the deceased's body to still be intact and relatively fresh.