Release bearing or pressure plate are possibly worn/damaged, or possibly even a bent push-rod.
Although don't take what I said as a definite, just a guess.
Perhaps other users will have more ideas about this issue.
When in neutral and you press the clutch in, does it stick then too?
And how does the clutch feel when you press the pedal? Is it smooth or rough? Does it possibly feel stiff then smooth or the other way around at all?
Just to have an idea if it's the cable or the other parts.