The Mercedes-Benz W221 is a chassis code of S-Class, the successor of the Mercedes-Benz S-Class (W220) and the predecessor of the Mercedes-Benz S-Class (W222). The S-Class are the flagship vehicles of Mercedes-Benz and each generation typically introduces a range of technical innovations and developments that over time will find their way into smaller cars.

Can we draw the following conclusion?
The W221 is the successor of the W222.
No