...Greet those who belong to the family of Aristobulus.
Romans 16:10 ESV

Aristobulus himself is not greeted, but his household is. This could include Aristobulus, but it more likely refers to believers within his household, which could have included family members, slaves, and hired servants.

There was an Aristobulus who was a grandson of Herod the Great. Although he died in 7 BC, he had been educated in Rome, and some of his descendants lived there during Paul’s ministry. In Roman custom, families often adopted the name of a famous ancestor as a surname, so It’s possible that this is the household being greeted, but by no means certain.