We are what we eat: a blend of tastes, recipes, cultures and habits. The kebab, a beloved, consumed, opposed, and now gentrified dish, represents and embodies all these tensions. Meanwhile, Turkey wants the döner kebab to be recognised as a traditional Turkish speciality, as pizza is for Italy.
German döner is genuinely different from either Turkish döner or shawarma: It's bread with kebab meat (or something similar to kebab meat, but made from cheap meats and filler content), onions, tomato, cucumber, and pickled white and red cabbage and a sauce (this varies regionally, e.g. we have the trifecta of joghurt/herbs, garlic mayo, and sweetish chili sauce).
[Oh, and the kebab meat itself can also be replaced with, most commonly, falafels ("Falafel-Döner"), or in some cases, seitan. But even if you stick with meat, you can usually choose between cow and chicken, with the original sheep meat being the rarest option.]