Including a character from another country, ethnicity, or culture in your story adds texture and interest. Unless it’s already one with which you’re familiar, however, be sure to research it so your details are accurate. Otherwise, those who know better will either think you’re clueless or even be offended.
One of my favorite movies is “My Big Fat Greek Wedding.” It demonstrates the concept of culture shock beautifully. Stories always need conflict, so this is another way you can create some between your characters. It’s also fun and interesting to learn about other places. If you’ve always lived in the same place your entire life, you may not realize how different even the state or country next door is from what’s familiar to you.
When I worked for NASA they had us take Cultural Awareness training since we were working with people from all over the world. They pointed out that cultural norms are not right or wrong, they just are. It’s unfair to judge another culture based on your own because you simply don’t know how they evolved. Learning about the history of an area is another way to understand the underlying programming for individuals who either lived through it or its aftermath.