Redmi Note 5 Pro’s Face Unlock works using AI (artificial intelligence) and its 20MP selfie camera. Unlike iPhone X which uses hardware-based FaceID for facial recognition, Redmi Note 5 Pro uses the front camera for the function, so the performance of the Face Unlock is highly depends on ambient light.
A little about Redmi Note 5 Pro and its specifications. The device was launched a week ago along with a mid-ranger Redmi Note 5 and as a successor to Redmi Note 4. Below are the highlighted features of the device. Redmi Note 5 Specifications:
How to get Face Unlock on Redmi Note 5 pro
- To get this feature, your device should be updated to MIUI 9.2.4.0. 
- If you have not received the update notification for build MIUI 9.2.4.0.NEIMIEK, check it manually by going to Settings > About phone > check system update. If update found, just update your phone. 
- After updating your device, go to Settings Lockscreen & password > Add Face data > and register your face. That’s it. Now, here is how to enable the feature on your device. After registering your face, go back to Seetings > Lockscreen & password screen, tap ‘unlock using face data’. You are done!