Some facts about FCC callsign policies that I hope will clear up a lot of misunderstanding. (Pat, please pay close attention, since you've been a prolific source of misinformation here!)
First: just because the WCBS calls are leaving AM doesn't mean WCBS-FM or WCBS-TV have to do anything.
The FCC doesn't care whether an FM or TV station's callsign includes the -FM or -TV suffix *unless* it's needed to differentiate from an AM station, which never has a suffix.
There's no reason WCBS-TV can't remain WCBS-TV if it wants to. Or, it could do what WNBC-TV did and become just "WCBS." But really, why bother?
Because, as others have mentioned, control of the base "WCBS" callsign still rests with Paramount, for two reasons.
First, the FCC policy says that whoever's had use of the base callsign longest can control whether any other owner can use it on other services.
As the corporate successor of CBS, which first used the WCBS call across all three services in 1946, Paramount has final say about whether it will grant permission to any other licensee to use "WCBS" anywhere else - AM, LPFM, LPTV, whatever.
And Paramount has already sorted out that issue. The contract for selling the CBS radio stations to Entercom is public and anyone can read it and understand what it says.
For the four radio callsigns that included the letters "CBS" (WCBS and WCBS-FM in New York, KCBS San Francisco, KCBS-FM LA), Entercom and its successors have until 2037 to keep using those calls. They were required to stop using the CBS Eye logo in 2018, and there's a provision that if any of those four stations change format, they have to change calls.
That's why WCBS is becoming WHSQ. It has to.
The agreement also said Entercom can't move those calls anywhere else. They can't put WCBS on 1010, for instance.