We can't give you an exact answer if we have to guess the make and model of the cable box and surround system.
If the cable box doesn't have any audio outputs then you can use the audio output of the TV.
If neither has any audio outputs you need an HDMI input selector with audio extraction like this one. https/www.monoprice.com/Product?p_id=5557&kpid=105557&gclid=CPPY2sLnwcYCFYIXHwodhY0FTw
We can't give you an exact answer if we have to guess the make and model of the cable box and surround system.
If the cable box doesn't have any audio outputs then you can use the audio output of the TV.
If neither has any audio outputs you need an HDMI input selector with audio extraction like this one. https/www.monoprice.com/Product?p_id=5557&kpid=105557&gclid=CPPY2sLnwcYCFYIXHwodhY0FTw