I was wondering what a conditional offer from Cambridge, specifically mathematics at Trinity College, for an international (American) student might look like. Would such an offer just require 5s on any remaining AP exams, or would it also involve the STEP test?
The conditions won’t relate to your nationality, they will relate to the standard offer for the qualifications you are presenting.
It would be exceptionally rare for a Maths offer from Cambridge to not include the STEP paper as a condition, in addition to any other exam conditions. If you do/did not submit enough APs with 5s in appropriate subjects then the remaining ones would also be part of your conditions.