A hybrid score is one where the orchestra is only part of the whole. There may be synths or a rhythm section (rock band). It is extremely rare these days for a score to be only live orchestra. Even if all elements are live, it is very common to record things separately. We never record choir at the same time as orchestra. Soloists adding ethnic elements are also nearly always recorded on another session. This means we must always be alert and aware of what else may be going on so we in the orchestra can tune and groove with them.