... know for a fact, because even if I did know, I wouldn't know.
There is a huge US Naval base there, that has been there for over 100 years.
From wiki:
Guantanamo Bay Naval Base (Spanish: Base Naval de la Bahía de Guantánamo), officially known as Naval Station Guantanamo Bay or NSGB, (also called GTMO, pronounced Gitmo as jargon by members of the U.S. military[1]) is a United States military base located on 45 square miles (117 km2) of land and water[2] on the shore of Guantánamo Bay at the southeastern end of Cuba. It has been permanently leased to the United States since 1903 as a coaling station and naval base, making it the oldest overseas U.S. naval base in the world.[3] The lease was $2,000 in gold per year until 1934, when the payment was set to match the value in gold in dollars;[4] in 1974, the yearly lease was set to $4,085.[5]
Since taking power in 1959, the Cuban communist government has consistently protested against the U.S. presence on Cuban soil, arguing that the base "was imposed on Cuba by force" and is "illegal under international law." Since 2002, the naval base has contained a military prison, for alleged unlawful combatants captured in Afghanistan, Iraq, and other places during the War on Terror.[6] Cases of alleged torture of prisoners[7] by the U.S. military, and their denial of protection under the Geneva Conventions, have been criticized.[8][9]
The 1903 lease has no fixed expiration date,[10] and as such it can only be ended if the US Navy decided to abandon the area or both countries agreed mutually to end the lease.
I don't think there is a need for the US to be there, but I understand why it's there and why Cuba can't force the issue. That sub is no particular provocation, but in terms of international treaties it takes a meeting of two minds to break them. Only Trump has ever unilaterally voided treaties, with Russia, and over nuclear weapons. Camp Gitmo is an abomination.