Even if we survive the looming 90-year drought and the unknown ultimate consequences of climate change, and even if anti-aging research pans out and you can hang in there a couple more billion years, eventually we're all toast.
There's one possible natural out, a small chance — about 1-in-100,000 — that during all this swelling the sun will lose enough mass so that it loses it's gravitational grip on our planet. Then we'll be lost in space, a sunless planet wandering aimlessly in a colder, darker and eventually perpetual night. So we'd all freeze.
There are a couple bright ideas for how to keep the human species going, assuming anyone is around in the future to execute the schemes. We could simply move to Mars or beyond, once we develop the right technology. Or we could, in theory, grab an asteroid somewhere and use its gravity to gradually lift us into an ever-larger orbit around the sun so we stay just beyond the fringe of the frying pan.