CBS has been mentioned to be unlikely in the Starz talks due to the recent Viacom/CBS Deal by the Redstones.
No surprise. Once the merger happens, they'll have more traditional cable channels than they know what to do with. They don't need to add more. They will have Paramount Studios to work with, so they don't need to spend outside money on content acquisition. If they need anything, it's not anything having to do with traditional platforms. It's all about their own digital space. They already own Pluto, so that's a good start.