A tie can still be appropriate for an in-person consulting interview, but office norms have become less uniform and the invitation should take priority if it gives guidance.

If you are unsure, a conservative formal choice is usually safer than looking noticeably underdressed. At the same time, some offices now treat a suit without a tie as fully professional.

The relevant factors are geography, office culture, role seniority, and whether the interview is formal or part of a more casual recruiting event.

If the instructions are silent and you cannot infer the norm, asking recruiting is fine. The outfit should help you look polished and comfortable, not become another source of stress on interview day. When in doubt, being slightly more formal is usually easier to recover from than arriving visibly underdressed for a formal interview.