t means that they win in two different ways. I searched on the phrase and think I found the web page you were reading. It explains that they win in two ways: Win #1: "Throwing a Thanksgiving celebration takes a little planning, which explains why the average American splashed out $448 ahead of the holiday in 2021." Win #2: "But that’s only one element of Thanksgiving spending, because the day itself—and the weekend that follows—is the busiest shopping period of the year." So they win twice. They win before the celebration as people spend money preparing for the celebration. Then they win a second time, when people spend money on "the day itself and the weekend that follows.

This expression means thats the marketers win big during Thanksgiving. Please feel free to message me if you need any help with English😁

It obviously either means that they win twice or that they win in two ways. Without more context, it's impossible to be more specific.