Not to mention, some identities may split or merge. An example from fiction that I feel handles this particularly well is Lois McMaster Bujold's Vorkosigan books. Many of them center on a planet called Barrayar, and the people of that planet definitely have a distinct "Barrayaran" identity. But it becomes clear, some ways in, that the people who initially colonized Barrayar were primarily French, Russian, and Greek (IIRC), and this is reflected in physical descriptions of Barrayarans as well as the names of cities and soforth on the planet.

@Mołot I've added an edit which explains my thinking on this a bit further, though I agree with you that I structured my answer in a way that buries that a little bit. I can restructure it to surface that more explicitly if you think that would be valuable.