Ableton Live's Follow behavior keeps the Arrangement view scrolling automatically so the playhead stays visible as your track plays, instead of running off screen while you sit still. It's a small feature but it changes how you navigate a session, especially on longer arrangements where you'd otherwise lose track of where you are.
Follow is on by default, but you can toggle it off when you want to work on a fixed section of the timeline without the view jumping around, then switch it back on with Cmd Shift F on Mac or Ctrl Shift F on Windows.