The 3rd Cuban War would be a proxy war between the United States and China in Cuba lasting from 2019-2021. It would be the first proxy war of Cold War II.
Eurasian Union support, 2018
In 2018, Russia, Belarus, Kazakhstan, Kyrgyzstan, and Armenia would form a union called the Eurasian Union, and this new union would ally with China to compete with the United States and European Union, officially starting Cold War II.
Cuba, as a communist country, is still heavily influenced by the former Soviet Union, and therefore still has deep ties with Russia. The ties get deeper with the formation of the Eurasian Union, as Cuban leader Miguel Diaz-Canal would announce support for the Eurasian Union. He would once again cut off ties with the United States and its allies, and increase government power in Cuba.
The increase of government power would make many Cubans angry. In November 2018, there would be a large riot in Havana that would overwhelm the weak police force, and would force Miguel Diaz-Canal to retreat from Havana to somewhere in Matanzas. But on his Twitter page, he would talk about bringing the protesters to justice when the violence clears up. This tweet would ultimately cause civil war.
Civil War, 2019-2021
The First Battle of the Cuban Civil War would start in Matanzas in January 2019. The United States and United Kingdom would agree to send support to the capitalist army, and China would agree to send support to the communist army. The Eurasian Union would not get involved, as crisis would be happening in Ukraine that would be leading up to another proxy war.
Throughout 2019, the US would send a fleet of submarines and aircraft carriers surrounding the island of Cuba to block off Chinese support. In October of 2019, China would officially announce withdrawing from the Cuban Civil War. With no support, the Cuban communist government and Miguel Diaz-Canal would be sent to exile in the Mensura National Park.
American and British soldiers would be sent home for the holidays, and the 3rd Cuban Republic would be officially declared to be the official government of Cuba by the United Nations, even though the Civil War still wasn't over.
On New Years Day, 2020, exiled Miguel Diaz-Canal would take advantage of the widely celebrated holiday as a chance to attack the US. So, at around lunchtime that day, they'd fly helicopters from Cuba to Puerto Rico, and would bomb the island of Puerto Rico.
The bombing of Puerto Rico, being the first attack on US soil since 9/11, would immediately trigger US investigation of Cuba to find Miguel Diaz-Canal and his communist army and have them killed for treason. There'd be a drastic increase in Puerto Ricans in the US army who'd go serve in Cuba.
However, the war in Cuba would be losing support after the start of the proxy war in Ukraine. More military service men would be deployed on a base in Poland and Ukraine than in Cuba. This would keep the US military from finding Miguel Diaz-Canal for almost a full year.
But then, in February of 2021, Miguel Diaz-Canal's hiding spot would be found. Miguel Diaz-Canal would be handcuffed by the soldiers and taken to Havana, where he would be graphically beaten and tortured to death by many angry Cubans.
New Cuba, 2021
The Cuban Civil War would be over in February 2021 with the death of Miguel Diaz-Canal. Even the Eurasian Union would recognize the 3rd Cuban Republic as the official government of Cuba.
Cuba would become a major close ally to the United States. Cuba would even join NATO, adding the number of North American NATO Nations from 2 to 3.
The tourism industry in Cuba from American, Canadian, and European tourists would skyrocket. Many hotels and casinos would be built along the coastlines of Cuba, and Cuba would become the 3rd most toured country in the Americas right behind Mexico and the United States.