Display black out But laptop working fine

If everything is working on your external monitor, this is likely to be an issue with the screen, or the display cable.

Does this behavior seem to change if you move the screen? If so, I would have a good look at the cable nd inspect for damage.

The touch part of the screen, as well as backlight run independently of the image displaying on the screen. if the other two work, but there’s no image and moving the screen doesn’t seem to make a difference chances are you’re going to need a new display. It could also be a cable issue, but it is more difficult to tell if behavior doesn’t change with display angle