Why does my laptop screen turns black while while using it?

We definitely need more details to help you.

When did this start and what other circumstances does it appear in? Such as only when the battery gets low, only when you're connected to ethernet, only when when watching youtube, etc.?

Does it turn black for a second or for a minute? Or until you power the device off and back on? Does it turn black when you tilt the screen or when you connect to wifi or after 15 minutes of use or any other repeatable, consistent stimuli? When it turns black, does it still output video signal via on-board HDMI or VGA ports? Does it still continue to make sounds through the speakers or do other such things?

When it turns black, is it screen off black, or screen on but no image displayed black? Do you still see the mouse cursor moving around the black screen or nothing at all?

Have you tried resetting or updating your display drivers, chipset drivers, CPU dirvers, or BIOS? Have you tried in-place resetting the gpu with Windows+Ctrl+Shift+B while the screen is black?