CVS’s retail media network is turning on self-serve advertising for the first time through a deal with The Trade Desk, a move that brands have wanted so they could control ad campaigns and get more transparency, according to Parbinder Dhariwal, VP and general manager, CVS Media Exchange.

CVS Media Exchange and The Trade Desk announced their partnership today during the Cannes Lions International Festival of Creativity.

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Until now, CMX has been a managed-service product, where brands in CVS stores work with the retailer to place ad buys, which can appear across the internet, including on Pinterest. The new arrangement puts CVS audiences inside The Trade Desk, the demand-side platform that many brands use to self-service their digital ad campaigns. The Trade Desk has made several deals with retail media partners, including Kroger, Albertsons and Walgreens. Meanwhile, Walmart has a bespoke integration with The Trade Desk that underpins its Walmart Connect DSP.

“We’ll give all of our partners who run their self-serve through The Trade Desk insight into media spend and that will subsequently also help us think about how we reduce waste in the ecosystem,” Dhariwal said. “And this is why our suppliers, advertisers, that they’ve been pushing us further to really come to the table with that self-serve opportunity, because it provides that level of transparency.”

The “transparency” is about showing advertisers “the costs associated with buying our media,” Dhariwal said. The self-serve option also is a typical evolution for retailers that are becoming more intertwined with the digital ad landscape. Retailers can offer brands in their stores traditional “shopper marketing” services, which help promote products in stores and appear on websites and apps through managed service arrangements with the retailers. But there are several brands that have become adept at managing their campaigns and want controls across the ecosystem of retailers, according to Ben Sylvan, VP, data partnerships, The Trade Desk.

“If you’re a brand marketer, and you are a big agency, you have a lot of programmatic expertise,” Sylvan said. “You have a lot of specifications around how you want to reach buyers, where you want to reach them … and they don’t want somebody else buying media on their behalf.”

Retail media has become one of the top tech topics at Cannes with the attendance of heavy hitters in the space, including Amazon and Walmart. Last week, ahead of Cannes, Albertsons Media Collective signaled an expansion of its connected TV footprint. The retail media network helps brands use its data to place video campaigns through demand-side platforms, including Google Display and Video 360, The Trade Desk and Freewheel. The media networks are growing, too, beyond just retailers, with even United Airlines and Chase bank launching them.

Part of the conversation around retail media networks revolves around setting up standards of transparency and measurement, as was one of the goals mentioned by Dhariwal, as well.

CMX is hanging its first banner at Cannes this year, with a beachside meeting space, Dhariwal said.

Also read: How much brands pay to advertise at Cannes

Retail media has become increasingly important because brands are seeking more data points to access, as parts of the internet restrict consumer information, hindering ad targeting and measurement. Google’s plan to shut off cookies on Chrome web browsers next year has been just the latest sign of how signals are being cut off from marketers online.

For its part, CVS has offline sales data on millions of customers and a loyalty program, ExtraCare, with 74 million members. On The Trade Desk, programmatic ad buyers have what are known as trading “seats,” where they manage their campaigns online with the ability to target highly segmented audiences based on their shopping behavior.

“You can reach verified buyer data from CVS and you can essentially program our platform to bid on everybody who is within that audience,” Sylvan said. “You get this huge, scaled audience of verified buyers within your category and you bid against all of them.”