Interstate among them: in trade, customs, labor ...
Discrimination can take an open form, such as a ban on entry into the United States from several Muslim countries, accompanied by a statement of the president that the country needs Norwegians more. And hidden - as a grouping by compatriots in Moscow, hiring only men or women, treating people with disabilities as unnecessary spoiled creatures, oppressing or re-educating LGBT+ people.
If we want to survive, we need to stop creating self-interference in the form of this archaism.
And if somewhere they overlap the border for the movement of certain goods, this is temporarily for profit of the smallest part of humanity, for all others it has profound negative consequences, that was verified with history. We should already take into account the environmental impact of each such movement, but we still just give the decision right to a small group of greedy tyrants.