Team Fortress 2 is having a 3 month event codenamed the Gunmettle Campaign.
Buying into the Gunmettle campaign which costs $5.99 will allow you to take on Gunmettle contracts. You will be assigned two skill-based contracts each week, every contract will have its own unique challenge with numerous methods of attaining contract points.
Completing these contracts will yield you skinned weapon similar to the CS:GO skins. These new weapons will have six grades of rarity just like CS:GO rating from Factory New to Battle Scarred.
Buying in the Gunmettle Campaign will also put a Campaign pass in your steam inventory, this coin keeps track of your progression in contracts. The coin will level up as you complete more contracts and will be put on a scoreboard.
The Gunmettlee Collections are guns avaible through the gunmettle update. Weapons from Teufort and Craftsman collections are only available by completing contracts.
While the powerhouse and concealed killer collections are only available through weapon cases.
Unlockable cases now also have the chance to give your weapon a Stat Module similar to CS:GO’s Stat Trek
Just like in CS:GO your newly obtained weapons will have new in-game animations.