By now, it's no longer breaking news that CVS Health (CVS) - Get Report is buying Aetna (AET) for about $69 billion.

The cash and stock acquisition combines a pharmacy company with a major U.S. health insurer. Management expects the deal to close sometime in the second half of 2018. That's likely dependent on whether regulators want to drag their feet on approving or denying the deal.

But what kind of implication does it send around the market? One could make the case that it hurts CVS competitor Walgreens Boots Alliance (WBA) - Get Report , as a tandem pharmacy provider and health insurer could help funnel sales away from the latter or toward the former.

One could also make the case that this is a negative for Humana (HUM) - Get Report , given that a combined CVS-Aetna may help lure away customers to Aetna. On the flip side, M&A investors could argue that with a $37 billion market cap, Humana may be an attractive takeover target -- say, for Walgreens.

Then there's the question of Walmart (WMT) - Get Report , which also has a pharmacy component. While it may not feel much of a pinch in the short term, pharmacy retailers teaming up with health insurers may leave Walmart out in the cold. After all, how many will flock to Walmart pharmacies when there will likely be incentive to use a coverage plan that includes both insurance and pharmacy benefits.

It also leaves question marks for Amazon (AMZN) - Get Report . Recently the discussion slid to medical device sales over pharmaceutical distribution. While the former could have potential, the latter seems to be ripe for Amazon's model. But unless Amazon starts a Healthcare Marketplace -- which at this point, wouldn't surprise anyone -- could it too be left out?

CVS is already undergoing same-day and next-day delivery initiatives to appease customers, while tying up with Aetna could drive further expansion. With Walgreens hypothetically nabbing another health insurer, Amazon could suddenly find itself with little wiggle room in the market.

WATCH: What Does CVS's Aetna Acquisition Mean for Amazon?

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This article is commentary by an independent contributor. At the time of publication, the author had no positions in the stocks mentioned.