Sony's Q2 FY results: 113,6m PS4s Sold, 45,9m+ PS Plus subcriptions as of September 30th, 2020. 107m+ Active monthly users.

[Sogreblute]

Seems the PS4 is still doing good, especially on the software side.
I think PS4 will reach 120 mil, but not much beyond that. It's done in Japan, it's getting there in the US, while EU is the one holding it up.