After re-watching the sizzle reel for the remaining episodes of Flash I noticed about a minute into it that Savitar and Killer Frost are sharing a rather emotional look with each other. Back in 3x07 Savitar’s acolyte Craig said he had “special plans” for her and in 3x21 when Iris asked Killer Frost’s reasons for wanting Savitar’s memories restored, she said “That’s my business”. I think Savitar may have feelings for Killer Frost and that's why he sought her out and because he's a future Barry that's why Killer Frost is so willing to trust him. I’ve suspected for some time now that Caitlin may actually harbour feelings for Barry but has kept quiet because she knows how much he loves Iris, so maybe she’ll be more willing with this version of Barry as he doesn’t have an Iris to hold her back.
It would also make sense since Caitlin is basically a magnet for the darkest of all the Arrowverse villains so why wouldn’t Savitar have a thing for her? Zoom did. I don’t mind admitting I have always been a bit of a Snowbarry shipper but simply because of how Olicity turned out I’m glad they haven’t pursued it but this could be a way to feature it without breaking any rules. Savitar and Killer Frost can actually relate to each other quite well. Both are cursed because of Flash’s recklessness and are condemned into an existence that neither deserves that ultimately drove them both insane from unbearable loss and pain, and want nothing more than for it to end. Maybe both experiencing absolute loss is what will draw them to each other to make each other whole again? After all both may now be deranged human beings who want to be seen as gods but they are still human no less and they still have feelings. If Caitlin does regain her sanity it could create tension between her and Iris because even though Savitar is future Flash they're still the same guy, and Caitlin having affections for Savitar means by default that she has affections for Flash.
Just a thought but the way Savitar looks at Killer Frost in the trailer implies there is something there. Also because of his accelerated healing which is even more amplified than Barry's, Savitar is the one character that Killer Frost could be with.