None? It is not certain any country will benefit. Countries built their infrastructure and population centers according to the weather of the location. If the weather changes probably every country will have to adjust.

If you are asking which area will benefit from climate change I would say Siberia as it will become increasingly important due to the northern corridor remaining ice free and because a lot of people will be displaced by weather/sea level. And that place is empty. Additionally, it has nice farming soil which right now is not used since there are easier places to farm but in a warming world this could change