I've had issues discussing this too, and I believe its possible however the possibility doesn't mean it is achievable that is theoretically we can make it possible it is a lot more difficult when we try to make it practical. I believe the only way to make this possible man will actually need to run past the speed of light or run farther than the speed of light that way someone can possibly travel into the future that is the nearest future presumably the next day, so I can explain how it's possible to take a trip to the future that is the nearest because the future is not yet shaped, however the past events of yesterday and yester years or even centuries ago has happened so it will be difficult to actually go back in time or travel back in time, it's easier to go to the future, rather than the past change any happening so going back in time will be more difficult and actually impossible both practical practically and theoritically as well.
But it will be easier to go back in future in theory and the only way for this to happen is if one can run past the speed of light or run faster than the speed of light so let us say this is actually possible for someone to run faster than the speed of light then to be easier to actually travel into tomorrow all travel a day after tomorrow however what I don't know is if one can actually meet his other self. All these are actually theoritical terms and like I said we take someone to travel further than the speed of light of which is basically impossible for this generation or this century or even centuries to come.
So I won't call time travelling an illusion or a reality the reason why this is so is because illusion means it's a mirage or facade but it is neither and it isn't a reality because it is only theoretically possible just like I mentioned the only reason or the only way which man can actually travel to the future. Will be difficult to actually travel back in time I do not know the things that need to happen for this to be possible but the circumstances is actually very difficult. So in general time travelling can be possible but is currently not possible