Do you mean using only Renoise native fx and commands?
If so, I don’t know if there’s a way to do a vocoder with just Renoise… you could get some pitched modulations and stuff with commands but it wouldn’t be what you’re looking for. As for fine tuning, I suppose you could chop a vocal into slices and fine tune each one, and then sequence the slices back in the correct order… but that would probably drive me insane eventually!
Renoise is good for creative processing though, just play around with the bundled effects. I would try to avoid actively altering the pitch of the vocal, because it’s really just a long sample and it will drift out of time if you start messing with the pitch/playback speed.
Now if you’re open to using third party plugins, you can definitely do a vocoder in Renoise, but it isn’t very intuitive to setup. There’s tutorials out there and also free vocoder vst’s. I’ve used the Melda Talkbox one myself and can verify that it works within Renoise.