What's the Name of That Book??? discussion

I read this early 2018 I believe. This book from what i can remember is in a world that's in an ice age; it's in the future a bit so there's some futuristic technology. It revolves around a young girl leaving the relative safeness of her hometown to try to find her mom who was lost on a mission into the snowy wilderness. She meets up with this guy named Luke and he helps fly her to the place where her mom used to work. From there they go on a mini snow wilderness adventure to a place. POSSIBLE PLOT SPOILERS AHEAD







(POSSIBLE INACCURACIES I'M TRYING REALLY HARD TO REMEMBER ALL THIS) They find a hidden village from like caveman times and find her mother living with them. Somehow the cavemen are still alive. The antagonist tries to kill the cavemen people and succeeds with killing a few but the rest get a away. There is also something about a hidden planet that the antagonist knew about but nobody else did and it MIGHT have something to do with the ice age.
Sorry that I didn't remember everything exactly I just really hope somebody's able to find something.
Thanks!

Julie ~~
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