Atletico Madrid got an additional player for the defense from Chelsea, namely César Azpilicueta. Because his contract expired at the end of June, César Azpilicueta's status became a free agent and Atletico took advantage of this opportunity to secure the services of the Chelsea veteran. His contract with Atletico lasted for two seasons and it was a good deal for César Azpilicueta to finish his career at Atletico. Diego Simeone certainly can't wait to give direction to the former Chelsea captain and his experience will certainly provide motivation for other Atletico players.
Source:
https://twitter.com/FabrizioRomano/status/1675030473834389505