Time travel in the future is already possible... well electricity and photons do move straight in the future faster than anything
and we humans travel in the future for each second passing but at a slower rate.
However time travel isn't possible,as already pointed out by other users when traveling back in time you automatically cancel the reason you traveled back in time in the first place.
However there are 2 ways in which you could give the illusion of traveling back in time.
1)When traveling back in time you don't actually really go in the past but create a clone of your universe with a different time lane, however it doesn't have any whatsoever effect on the original universe.
So if you go back in time to save the life of someone you will not save them, they will remain dead in your universe but you will create a clone of them in another universe.
2)Dying, being dead could be the philosophical equivalent of traveling back in time. As you didn't exist before your birth you will stop to exist after your death, you could metaphorically consider dying as returning back to your past black dark and void nothingness-