"Cortana. Who are you?" Not that she hasn't already pulled Sombra's ID from the Legion records, mind. Humans who aren't used to smart AI--and clearly this one's not--get a little jumpy about that kind of thing, so in the interests of conviviality and also not making things harder on herself, Cortana just won't mention it.

Shadow. And goodness, isn't she busy being pleasant all over the public channels?

Clearly up to something. Cortana can respect that kind of duplicity.