All dishes are different around the world - spaghetti, sushi, pizza, hamburger, etc. Sometimes a dish is luxury in one country and casual food in the other. It always differs, even across regions of one country, regional influences, etc. It doesn't mean it's a different dish by definition.
No, literally - the middle-eastern "kebab" is called cevapcici in Europe (at least in Ausria/Germany), it's a totally different dish from dönner kebab.