If you try to start Hollow Knight and only get a black screen that turns off after a few seconds try you might have a graphics card that does not support Vulkan or are missing drivers.
If you are like me and playing on a laptop without dedicated graphics card changing to OpenGL might help, try this:

1: Open Steam

2: Right click on Hollow Knight and selecet Properties

3: In General -> Launch options, write 	"-force-opengl" without quotationmarks.

4: Close Properties

5: Launch the game again, it should now start without issues.