4 Reasons Why Cersei will Probably beat everybody else [Prediction]
1. Geography: She is the lowest on the map from where the White Walkers come from. This puts her at a significant strategy to either be saved from the fights with them, interfere with the fights, or win the fights. She will more than likely dishonor the "truce" she made to help fight them. I believe this may push Jamie away from her for good since he is changing.
2. She has Qyburn: Note the moment when Qyburn took the White Walkers hand. He marveled at its fascination, I consider it a prelude to that He may very well be able to create similar armies and fighters from this.
3. The Iron Bank of Bravos: Having paid off the entire Lannister/Baratheon debts with what was plundered from the Tyrells. The bank granted them access to more funding. This is a serious problem because she may now be able to buy copious amounts of armies/supplies and other things.
4. Winter is here: Note: See Geography/Iron Brank of Bravos. They are in a better strategic position for winters arrival. They have access to more money than anyone else and can provide food for it.