The OnePlus 5T was released within just 5 months from the OnePlus 5, which left many OnePlus 5 owners disappointed for not having the tiny bezels and face unlock that was featured on the OnePlus 5T. As the face unlock is a software feature on the OnePlus 5T, the company have been getting a lot of requests asking them to bring it to the OnePlus 5.
https://twitter.com/getpeid/status/944915403398098944
In response, OnePlus CEO Mr. Carl Pei has confirmed on Twitter that the OnePlus 5 will indeed get the face unlock feature in a future software update.
No specific date has been provided as to when to expect the rollout and whether older OnePlus models will get the feature (which is very unlikely!).