CrossFire: Legends is the Mobile version of the popular MMO FPS game CrossFire. It was developed and released by Tencent, and use Gem as its currency.
CrossFire: Legends was released on May 26th (2018) for iOS and Android devices. It's the fourth version released after its initial launch in China (After VN and KR), and the official Global version of CF Mobile.
It runs on the Unity engine as opposed to the LithTech engine, simply due to Unity being quite popular for mobile games. The game went through a short closed beta test for Android players, before landing on the iOS Store on May 2018.