Cuba Arms Treaty
The Cuba Arms Treaty was a United Nations agreement signed by 130 nations in 1963, following the standoff between US and Soviet forces during the Cuban Metahuman Crisis.
The Cuba Treaty limits the use of metahumans in armed conflicts and create metahumans as a protected class of citizen. Later amendments limit production and use of autonomous drones (and in 2018, proto-sapient AIs) for military or police purposes. Countries signatory to the Treaty may not deport their metahuman residents and theoretically cannot force relocation (though America and others maintain Mutant Town and other districts that are a product of forced resettlement policies).
A number of nations refused to sign the accords, either wanting to weaponize their metahuman population or refusing to surrender the valuable Sentinel protocols. However most of NATO and the G20 nations agreed to abide by the rules of the treat.