I need one cell nomber for a person in usa

Cell numbers are usually "private" numbers and not listed. You would have to call the provider of the phone and find who to contact there. Get a sopeana for the records.

It will depend on the provider and how they have the number, for example, there are many pre paid cell phones that just can not be traced, you can pay cash for the phone at the store, load min each month and no one at all knows who owns that phone.