Data acquisition has always been a significant challenge at a hadron collider. The combination of high luminosity and finely segmented detectors yields data rates that far exceed what can be stored permanently. The problem has traditionally been solved using a trigger system, that performs event selection online. In many cases, the trigger system has relied on dedicated detectors, or detectors designed with the trigger in mind. We start by reviewing the state of the art in the field - namely the Phase-2 upgrades planned for ATLAS and CMS. We explore the particular nature of the trigger challenge for FCC-hh, and propose some options for further investigation.