In Istanbul you can possibly find best examples of many if not all of international cousines. It is a city for the all types of foodies.
But the good news is you really do not need anything other that Turkish food because it is just amazing.
For example, try getting proper cantonese dim sum in Paris or Barcelona. I only know 2 places in Paris that are halfway decent after having searched quite a bit. Or try searching for good Zhejiang food (the Hangzhou or ningbo style) in Europe.
And Chinese food in most of the US is bastardized to make it much sweeter and oily to conform to the taste there making it absolutely terrible and far from authentic.