I subscribed to EPIX though Amazon Prime Video not too long ago, mainly so that I could watch War of the Words and Condor.
I found that EPIX has more series that I like than some of the other subscription services, so I check it out from time to time to see what they have new. When I checked Amazon Prime Video on 2-04-23, my EPIX subscription was replaced with MGM+.
I did an internet search for EPIX and found the wikkipedia entry below to be informative:
MGM+, formerly known as Epix (pronounced epics and stylized as eᴘix), is an American premium cable and satellite television network owned by the MGMPlus Entertainment subsidiary of Metro-Goldwyn-Mayer (MGM), which is itself a subsidiary of Amazon’s MGM Holdings, Inc.