Cablevision has announced a deal with CBS that has some exclusive provisions: CBS will sell CBS All Access and Showtime streaming to Optimum customers of the Internet-only variety. Seeing as Optimum is a brand name associated with the American cable service, the Optimum-only criteria makes sense.
Currently, Cablevision offers HBO Now and Hulu services in the same way – in a bundle with their bill – and it's assumed that a CBS All Access or Showtime service would work in the same way. These kinds of packages are known as "cord-cutting" — essentially doing away with direct access to cable channel providers and opting for a streaming-only service. It adds to a recent trend within the past few years of going with stream-only providers like Netflix instead of the traditional cable-centric fare.
As of now, the eventual price for the Showtime and/or CBS bundle is not known.