AFAIK:

uses Schnorr signatures instead of ECDSA

addresses start with bc1p, not bc1q like V0 segwit addresses

has more abilities regarding multisig...before TR, when spending from multisig as P2SH or P2WSH, had to include pubkeys of all signers, whereas TR only has to reveal aggregate pubkeys & signatures. this may or may not involve cross input signature aggregation, which I'm unsure of current use/availability.