“Probably no stars will physically hit each other. There’s just so much space between the stars, but when Andromeda collides with us it’ll have a huge impact on the Milky Way. Some things will get thrown into the black hole in the middle, some stars will get ripped off and thrown away into space, so it’ll be dramatic. And the entire night sky will change.” - The Universe S1E9 Alien Galaxies
Of course, that’s gonna take a few billion years, and by then we’ll probably be long gone.