Thank you for coming for the interview.

Literal

Interview [to-に] honorifically-come-お越し [humble-received-いただき] [thanks-ありがとうございました].

Classic business keigo. お越しいただく stacks sonkeigo (お越し — honorific form of 来る/行く) with the humble auxiliary ~ていただく, creating a doubly-polite frame for acknowledging someone's visit. ありがとうございました is the past form of the gratitude expression, used after the action has taken place.