Smart Lock; Facial Recognition; On-Body Detection - Huawei NEXUS 6P Quick Start Manual

Emergency.
If you have a device that's set up for more than one user, you may need
to touch your image at the bottom of the screen to see your own locked
screen.
For more information, visit Set screen lock.

Smart Lock

You can turn on Smart Lock to keep your device unlocked when it's safe
with you—for example, when you're at a trusted place or when the device
recognizes your face. To use this feature, go to Settings > Personal >
Security > Smart Lock.
Trusted devices
You can set your device to stay unlocked while connected to a Bluetooth
device—like a watch, fitness tracker, headset, or car speaker system. You
can also set your phone to unlock when it touches an NFC tag.

Facial recognition

You can have your device unlock when it recognizes your face. After
setting a trusted face, every time you turn on your device, it will search
for your face and unlock if it recognizes you. Keep in mind that someone
who looks similar to you could unlock your phone.
Note: Face matching doesn't store any photos of you. Data used to
recognize your face is only stored on your device and is not accessible by
apps or backed up on Google servers.

On-body detection

You can have your device stay unlocked when you have it on you —
for example, if you're carrying it in your hand, pocket, or bag. The
accelerometer built into your device will keep your device unlocked when
it senses that it's being carried. On supported devices, on-body detection