McDonald’s is constantly striving to improve itself and to be more distinctive both in the United States and internationally. See, for example, “McDonald’s Shifting Gears”.
Here’s an example, as reported by Chris Snyder for Business Insider:
“When you think of McDonald’s, you typically think big golden arches and a red roof. This restaurant is much different. A unique McDonald’s in Freeport, Maine was installed inside an old mansion built back in 1850. It maintains the Victorian aesthetic and even offers lobster rolls for the complete New England experience. This is what it’s like.”
(Video from Business Insider)
This isn’t new. McD’s was doing lobster rolls when I lived in New England back in 1991. My understanding is that they have other regional additions to menus, but I’m not aware of specifics.