Do you mean WGN, or WGN America? If you are in the Chicago area, then the real WGN is part of basic cable because it is a local broadcaster. For others, WGN America will depend on which package you get.
To clarify, WGN has been split into two separate entities: the local Chicago channel, that carries programming for Chicago and its surrounding suburban area, and WGN America, the national station that plays on service tiers higher than Digital Starter Pack (it's available by subscription also). Both are owned by Nextstar Media Group, co-owner of Television Food Network (parent of Food Network and its sister Cooking Channel, alongside Discovery Networks).
WGN America used to be the WGN "superstation", carrying the local station's programming to the entire US market, but it became a standalone channel at the end of 2014. Its sister channel is Antenna TV.