And likely, up far north in the USA when it develops:
(1) Different battles/etc would happen on the USA's south border.
(2) USA schoolchildren would be learning highschool Nahuatl instead of highschool Spanish.
(3) The big USA navy base at OTL Corpus Christi might have a Nahuatl name.
And...
See https://www.telegraph.co.uk/news/2021/05/23/operation-unthinkable-churchills-top-secret-plan-invade-russia/ . What if this plan to attack Russia after the 1945 victory in Europe, had been attempted?
For OTL, see https://en.wikipedia.org/wiki/Battle_of_Crete . The Germans by paratroop drops early got hold of Maleme airfield on Crete's north coast and used it to fly supplies in. An Allied attempt to quickly recover Maleme airfield was delayed a day by a sea storm (bad weather) delaying Allied...
In WWII, what if Russia/USSR at start of war used the same railway gauge as western Europe? I recently saw a television program that said that in Operation Barbarossa, inability to use Russia's railways at once, proved crucial.
If another war starts in Korea, I see various POD's:
(1) North Korea invades South Korea
(2) South Korea and the USA invade North Korea to stop the missiles.
(3) There is a civil riot (caused by hunger?) in North Korea. Army units are sent to quell it, but instead join in, and the trouble...