Ozzie Nelson for one; never smoked or been around smokers but yet died from lung cancer (or so I’m told).
Ozzie started out as a bandleader, which means that he was around smokers, considering the era.
Smoking isn't the only cause of lung cancer although a major one. Anything that damages DNA in your lungs will increase risk. Dustin Diamond who also died of lung cancer two weeks before Rush, didn't smoke either. Neither did Andy Kaufman. Only about 10% of lifelong smokers will develop lung cancer over their lifetimes. That's because cancer development is a long complicated process ("oncogenesis") and a number of things have to go wrong over a period of years before cells turn cancerous. Being a smoker just gets the ball rolling.
Ozzie died of liver cancer.