If it isn't the cable, which is worth investigating, the transmission has to be removed to inspect the clutch and thrust mechanism. Whilst the transmission is out it always pays to replace the clutch as the labour is much greater than the parts cost.
We need to know the year, make and model of your car or truck to be able to figure out if or not it has a hydraulic clutch cylinder.
check your clutch cable for wear & tear, adjuster may be worn.