Congestive heart failure, bike crash, diabetes complications, skydiving mishap, stroke, motorcycle crash, cancer, backpacking fall, suicide, car crash, shot by a jealous spouse, emphysema, and so on.
You could pick your favorite, then live your life trying to get there. Or you could live your life how you want, day by day, and not concern yourself so much with the endpoint. A bit of a false dichotomy I suppose, but with age comes acceptance that life is temporary, and best if lived well for whatever time we have.