I've been frustrated for years that there is now lounge at MDW. The C concourse isn't a bad place to wait out a delay or connection, but always nice to have free snacks and drinks while you wait.
I noticed on the construction banners at MDW that a "shared use lounge" was being constructed, just past the TSA checkpoint, presumably after the bridge is done being widened -- kind of where the TSA Pre checkpoint is now.
I was curious for more info, so I contacted Chicago DOA on twitter and they said:
As part of the Concessions Redevelopment Program, Midway Partnership (our concessions operator) is constructing a common use airport lounge in the Central Market. MP already has a subtenant under contract, Airport Lounge Development. We look forward to this new service opening in late 2020
Airport Lounge Development's website says they are owned by Collison (same people who run Priority Pass) and give as an example of their work "The Club at DFW". I assume the other "The Club at XXX" lounges are also their work, and they all accept Priority Pass.
Given that there are no Business/First class seats flying out of MDW (except a handful a day on Delta), I think it is hiiiiighly likely this new lounge will accept Priority Pass too.