Please tell us some basic information before asking for help:
Model Name: Rog Phone 5
Firmware Version: UL-ASUS_I005_1-ASUS-31.0810.1226.84-1.1.145-2205-user
Rooted or not: no rooted
Frequency of Occurrence: ever
APP Name & APP Version (If your issue relates to the app): camera
Black screen in camera use in any app