Not all lung conditions are life-threatening. Even if you have a persistent cough, it doesn't automatically mean you have cancer. But you should go to the doctor and get it checked out.
Some conditions, such as bronchitis and bronchiectasis, can get worse or cause other conditions to develop or worsen so they need to be treated.
Some conditions such as emphysema and asbestosis can have serious health effects, so appropriate treatment is very important.