I read in some site that there was supposed to be a campaign in Enemy Territory and in that campaign you had a squad of AI soldiers with different abilities helping you in the missions. But that was cancelled.
https://www.gamespot.com/articles/wolfenstein-enemy-territory-canceled/1100-2910749/#:~:text=Activision%20and%20id%20Software%20cancel,component%20as%20a%20free%20download
.
Anyone here knows why exactly was that cancelled outside of "the single-player portion of the game did not progress as anticipated." statement ?
Also, has there even been any leaked footage of that campaign mode ?

There is an unofficial ET SP mod for RTCW:
https://steamcommunity.com/sharedfiles/filedetails/?id=2600685791
Also available on MODDB.