I mean it seems that the last installment in the franchise before the 2020 television series was a 1995 television film. So the series was dormant (with no new media) for a full 25 years. So if one was under 25 (or even 30, assuming they were not watching Perry Mason at 5), or simply was not American (given that Perry Mason is an American property), it would not be unbelievable for one to not know what Perry Mason was going into this television series.

If it helps, off the top of my head the only Rihanna song I can think of is “Shut Up and Drive”.