If an interviewer asks this question to a candidate that means he wants to know about the candiadates qualities and skills which will be benificial for the company.
If you have some extra-ordinary qualities and skills which is quiet useful for the company kindly answer the same.
Say if you are a good salesperson and have quality to convince people easily; you can answer that I have very good convincing skills; along with give an example too. It will help you a lot in getting the job.
