What are the differences between "They are from the north" and "They come from the north."?

"They are from the north" means that the group you're referring to originate from the north.

"They come from the north" means that the group you're referring to arrived from the north.

Neither of the first two sentences are as exact as the sentence, "they were born and raised in the north".

Neither of the first two sentences are as exact as the sentence, "they were born and raised in the south, but they just came back from the north."