I really like this documentary for both pre-departure for traditional study abroad and for COIL/international virtual education experiences. Watching and then discussing this film allows students to open up and be vulnerable about their own processes of becoming more aware of the cultural stereotypes they have of others as they prepare to interact more intimately through immersion or online interaction. If you don't have access to the whole film through your institution, cannot afford to purchase a copy, or simply want to use shorter film clips as part of a dialogue or written reflection activity, there are several excerpts available for free streaming from the Crossing Borders Education website. 

Many COIL experiences use English as the medium of instruction, with a mix of native and non-native English speakers participating. In some cases, it's a good idea to prepare the native English-speakers for these interactions by helping them to understand what non-native speakers may be experiencing. I would suggest watching a relevant film clip from the Crossing Borders Education film, "The Dialogue" and extract lessons from it in a debriefing discussion. Here is the link for that particular clip: https://crossingborders.education/films/the-dialogue/clips/ (#3 clip - "On speaking a foreign language").