You should be considering a cross border data transfer only if the individuals are “in the Union”.
The EU GDPR will only apply to personal data regarding individuals within the Union, while the nationality or habitual residence of those individuals is irrelevant. For example, a company based in the EU which is processing the data of Japanese individuals located in Japan will still need to comply with the EU GDPR. Consequently, the Japanese individuals will be benefiting from all rights according to the EU GDPR, even if these rights do not exist in their own nation’s laws.
When the data of EU citizens is processed outside of the EU by companies which are also outside the EU, then this is not considered to be “in the Union”. For example, the EU GDPR will not be applicable for a school which is based in the United States just because there is a possibility that one or several of its students would be EU citizens. In this case the processing does not take place “in the Union,” nor is the individual “in the Union”.