@dj1121 I think your code to get the results is correct for any market or language is correct. I have tried the same snippet and it does return results for ZH and EN language codes. This is the result for zh-TW
The first image for your search term is the following.
https://tse2.mm.bing.net/th?id=OIP.DVAVBrd-CTFnlWIbjwGoagHaE3&pid=Api
I think the issue in your case might be in setting the search term with respect to character encoding that is passed in the request to the API. You could also try the same search using postman to confirm and it should work fine.
The endpoint I have used in the above case is https://api.bing.microsoft.com/v7.0/images/search