Sergey Bogachev, head of the Solar Astronomy Laboratory at the Space Research Institute (IKI) of the Russian Academy of Sciences, stated in an interview that humanity has no reason to concern itself with what will happen when the Sun ceases to exist, as Earth`s biosphere will have completely transformed by that time.
He emphasized that this question holds virtually no practical significance for us. Bogachev pointed out that the first multicellular organisms appeared on Earth approximately half a billion years ago. During this immense span, dinosaurs emerged and became extinct, and mammals evolved. Yet, the Sun`s demise is still 5 billion years away—a period ten times longer than the existence of multicellular life. It is utterly impossible to imagine the state of the biosphere at such a distant future; it will undoubtedly feature different plants and animals, and whether humans will still exist is entirely unknown.
The Sun (Archival photo)
Furthermore, Bogachev mentioned that some scientists hypothesize that in about 3 billion years, our galaxy will collide with the Andromeda Nebula. This cosmic event could potentially eject the Sun from the Milky Way, or cause planets, including Earth, to be torn away from our star.
Rupert Blackwood 
Clement Ashworth