It’s not The Thing, but somethings are similar. Here what’s I remember: the action takes place in snowy, cold area, during killing other people have dreams about their relatives, in final scene there are 2 humans left, man and woman. During man stand over the abyss, woman has a conversation with monster/alien, witch looks like the man and she finds out, it is not human.
The Thing prequel from 2011? Or The Thaw, with Val Kilmar?
Another one that popped in my head was Cold Skin?