I feel like for as long as I've been alive, that question could be asked about something like 75% of CBS shows. They're successful, but I've never been able to say I know of anyone who watches them.
Network TV, in particular procedurals, are for and watched by older demographics. Which is why anybody in their 30s or younger doesn't know anybody who watches them. Your parents or grandparents probably do, but don't talk about it.
From a report in 2020:
"The report pegged CBS as TV’s oldest-skewing network with an overall median age of 63.2 in primetime. Even more recent shows such as
FBI (66.3) tilts to retirees. CBS’s only primetime series with a below 60 median age is
Survivor (57.3)."