in some transaction for

in (something) for (someone)

Involved with or a part of something in order to benefit from it. Why should we help you? What's in it for us? A boost to your resume is in it for you if you take this job.

in some transaction for someone

having value for someone; having a benefit for someone. (Usually a question: What's in it for me?) What is in this deal for me? There is a lot of money in it for you.
See also: transaction