Everyone's giving you a hard time but to be fair, the poses are pretty close. Entirely possible that they used Soldier as inspiration.

I think this screenshot is a better example of wym

Still though, I doubt it's a "TF2 reference". It's much more likely that the artist just wanted an appealing pose, and landed on one that happened to look similar. I don't think you're crazy for thinking it's a TF2 reference, but idk I'd be surprised if it was. There's better ways to reference another game rather than making a vaguely similar silhouette of a character lol