hold down the area above F8F9 otherwise black

I need to hold down the area above F8 and F9 without moving in order to turn on the screen. Otherwise, it remains black.

One day when I woke up my MacBook from sleep mode. I found that the screen was black, but the external monitor displayed normally. Then I discovered that by pressing and holding the area above F8 and F9 without moving, the display would work properly. However, once I released the pressure, the screen would go black again.

I can only use the MacBook with an external monitor, but during usage, sometimes the MacBook's screen would suddenly return to normal. As long as I don't adjust the angle of the screen, I can continue using it. However, if I accidentally move it, there is a high chance that the screen will go black again.

Is this a problem with poor cable connection? How can I fix it?