It's have sound but doesn't show the screen

Without knowing what model your television is, there's no way we can give you an accurate answer, so please edit your question to add that information.

If it's an older model LCD TV then it's possible the backlight could be out; you can check that by holding a flashlight up against the screen at an angle and seeing if you can make out a picture. If you can, it is most likely a backlight issue.

Otherwise, or if it's a newer OLED set, then the problem is elsewhere, but as I mentioned we can't even guess without knowing what TV you have.