In Biomutant, the Cold Suit is one of four armor sets designed to keep the player alive in unique hazard zones. That said, if you want to get the Cold Suit, you will need to head on over to Pingdish north of the Tree of Life in Yerpfields and solve a satellite puzzle. As a side note, make sure to pick up the relevant quest for the Pingdish, so you don't miss out on sweet, sweet XP.
After finishing the puzzles at the Pingdish, you will soon learn that you will need to head over Bangshelter 10E and clear it of all enemies inside. They will only be bandits like with the other suit locations in the game, so don't worry. Once you clear them, you can find the suit towards the back of the Bangshelter. When you get the suit, you will have enough cold resistance to survive in cold zones. However, you shouldn't only rely on the suit alone.
This is because you can easily get the same amount of resistance from upgrading or finding armor with cold resistance. Plus, if you use other armor, you will get better protection from other things while you are at it. That being said, we highly recommend getting other armor with better all-around stats over the suit.