in business / on business / in business with

in business
・会社や個人事業の営業の歴史
　We have been in business for 20 years.
・まだ営業しているか聞くとき
　Are you still in business?
・何かの計画を立て、その計画を実行するために準備ができた際に使える
　Okey guys, we are in business.
・（一般的に）ビジネスの上で
　Being sincere is very important in business.

on business
仕事のために
・Are you coming to America on business?

Reference source

• https://www.eigowithluke.com/in-business/