Okay, I guess that requires a little explanation. Minor spoilers up to season 5 ahead:
- The entire setting is essentially a settler scenario in a rebooted North America. Zombie stories are usually about the alleged evils of consumerism; this theme is entirely absent from TWD. About the only concession is the country club in season 4, and Andrea nicking some trinket for her sister in season 1. Instead, much of the focus is on survival in a hostile environment, about farming and hunting. The ruins of civilization provide the backdrop, but are rarely necessary for the story.
- TWD is about "common people". None of them would in any way be special in our world. Rick is a deputy, Darryl a hillbilly, Carol a housewife, Hershel a doctor-turned-farmer, and it goes on. Andrea is one of the few to even have a college degree. The show is about ordinary people doing extraordinary things, which I consider to be a very American trope. Compare and contrast this with GoT, where almost everybody is a noble (and the show suffers from that in my opinion).
- Much emphasis (maybe too much) is put on the importance of families - a notion that I think is more present in the conservative parts of the US than in Europe. To the show's credit, there's no homophobia associated with this.
- If you feel like it, you can make out a strong anti-government theme in the show. Government agents are at best well-meaning but ineffectual (Dr. Jenner, the National Guard) or far less competent than the "free" survivors (Alexandria) or plain evil (most of the Atlanta police department, or what's left of it). Is it an accident that the most prominent villain in the show fancies himself to be "the Governor"? Probably not.
I could probably go on if I thought some more but that's what comes to my mind for the moment.