Google has numerous ways for you to unlock your Android smartphone. There are things like trusted places, trusted places, trusted face, and on-body detection as well as the standard PIN and pattern unlocks. The newest one is what they call Trusted Voice, meaning you can unlock the device with just your voice. To unlock, you just have to utter the magic words: "Ok Google." Google warns though that this is a less secure way to unlock a device. But if you want ease for gaining access to your phone, you might want to try this out. Again, they have just started roll outs of the feature and only a few users have seen it in their settings at the moment. 

Source: Android Police