Many retail businesses have tried their hand at healthcare: the likes of Rite Aid and Walgreens scaling back their so-called medtail efforts. The fee-for-service makes it harder than it looks because the cost of primary care doesn't get cheaper with scale.

Groceries seem to have made progress with pharmacies, as Placer.ai has pointed out, and many have managed this for years. However, recently groceries have moved towards more extensive clinics. Kroger runs its Little Clinics, first introduced in 2003, in more than 225 the Kroger stores. There are additional locations in regional brands Dillons, Jay C Food Stores, Fry's, and King Soopers.

Placer.ai, which uses cell phone information to pinpoint the movement of people down to the property level, looked at the effects of a clinic in a grocery store on foot traffic, repeat business, and their customers' demographics.