I'm 22 don't drink or smoke but my urine sometimes is dark yellow how likely is kidney cancer the cause? or liver damage if i haven't smoked

No : Good don't smoke don't drink , at age 22 cancer is the least you have to worry about, most likely you are dehydrated, drink plenty of fluids, good food habits, and see your doctor.

Urine color can be: A tip to something wrong, but dark amber urine usually means it is concentrated, and you have not drank enough water. Liver does excrete bile and bilirubin and it can be filtered into urine, but at levels where your skin and eyes would be yellow. Smoking is bad, but unlikely to be related. A urinanalysis can answer these questions and answers cheaply and accurately.

Dehydrated?: The most common cause of dark yellow, sometimes strong smelling urine is simply that your body is concentrating your urine to conserve water because you are dehydrated. The next time this happens, try to recall what your fluid intake recently had been and start drinking a lot of fluids (your urine should start to lighten).