So, picking from features new to macOS in the last few years (if I'm understanding you correctly):
Off the top of my head:
system settings search
Airplay
Preview app's abilitiy to read characters in images (OCR)
APFS in general, but specifically snapshots and volumes that grow and shrink.
Syncing between apple devices
TouchID (I have it on iphone, but I have a MBA M1 coming with thouchID, and I'm looking forward to it. If it's good, I'll get a new magic keyboard for my Mini.)