On Monday, June 5th Apple will present its worldwide developers' conference (WWDC), an annual event where the company announces new features and products it's launching in the near future. While the focus is usually on new iPhones, Macs, or iPads, it wouldn't be out of character for the company to announce news about its various healthcare ventures as well. 

After all, it was at WWDC in 2014 that Apple first announced HealthKit. And in 2015 and 2016 the company announced a lot of health-related features for iOS, HealthKit, and the Apple Watch. ResearchKit and CareKit, the next two evolutions of HealthKit, were also announced at big Apple events, though not at WWDC.

At the very least, we can expect some updates to the health and fitness features on the Apple Watch or some updates on ResearchKit and CareKit from the stage tomorrow. But who knows? Apple could also surprise us with something bigger. Since the last WWDC, rumors, leaks, and meaningful public moves about Apple in healthcare haven't exactly been in short supply. Read on for a refresher on what we know, or suspect, Apple is up to in the health sphere.

1) FDA-cleared devices 

Based on emails exchanged between Apple and the FDA between 2013 and 2016, obtained via a FOIA request, MobiHealthNews reported last fall that Apple seemed to be working on two FDA-regulated devices in the cardiac space and an app for diagnosing Parkinson's. I speculated in a follow-up column that the cardiac monitoring device could take the form of a new model of Apple's Airpod wireless headphones.

As for the Parkinson's app, it seems clear that it would build on health applications Apple has previously featured in its public events: the ResearchKit and CareKit apps focused on Parkinson's. When it comes to HealthKit, ResearchKit, and CareKit, Apple has followed a pattern of building on each previous framework and climbing closer and closer to regulated device territory. So if or when that app is launched, it wouldn't be surprising to see it spotlighted at WWDC.

2) A wearable glucometer

More recently, CNBC broke the news that Apple has been working on a wearable glucometer -- possibly for people with diabetes, but possibly as an aid for food tracking and diet management in healthy people. This has been a longterm project for Apple but it's also a very tough nut to crack -- it seems unlikely it will be brought out on stage tomorrow. That said, Apple CEO Tim Cook has apparently been wearing a prototype around, so maybe it's further along than we realize.

3) Fruits of health-related acquisitions

Apple has actually made three different acquisitions in the last few years with ties to healthcare, and the influence of those acquisitions is likely to show up in Apple's coming feature and product announcements. In 2016, acquired a health data-focused startup called Gliimpse. The main innovation of the product is an AI engine that reads medical records (with patients' permission, accessing them via the patient portal) and breaks down and codes them into a standardized and readable language. This year, Apple acquired sleep monitoring company Beddit and Lattice, an AI company with historical ties to healthcare.

4) A mysterious partnership with Withings

We'll likely hear about this one from Nokia before we hear about it from Apple, but it's worth mentioning that recently when Nokia and Apple settled their patent suit, the announcement of the settlement included the revelation that "Apple and Nokia are exploring future collaboration in digital health initiatives". Nokia recently acquired Withings, a French maker of a line of connected devices that have long been compatible with Apple products.

5) Matchmaking through its Mobility Partners program

Through its Mobility Partners program, Apple connects different companies whose technologies could work well together. The program has been weirdly secret in the past, but recently the company has started to discuss it more. Notably for the healthcare space, the program united mobile EHR drchrono with telerehab platform Physitrack. One way or another, the tech giant is finding its way into hospitals.