From the BMW X5 2019 online manual
"Cornering light
In tight curves, for instance on mountainous roads or when turning, an additional, cornering light is switched on that lights up the inside of the curve when the vehicle is moving below a certain speed.
The cornering light is automatically switched on depending on the steering angle.
When driving in reverse, the cornering lights may be automatically switched on regardless of the steering angle."
Source:
https://www.bmwusa.com/owners-manuals.html