What 2 teams fought in World War 1?
If by "teams" you mean what there the names of the two sides in WWI. They were the Central powers and the the Allied powers.
The Entente Powers were the countries at war with the Central Powers during World War I. Triple Entente was made up of the United Kingdom, France, and the Russian Empire; Italy entered the war in 1915.
Japan, Belgium, Serbia, Montenegro, Greece, Romania and the Czechoslovak legion were minor members of the Entente.
The United States entered the war as an Associated power on the side of the Entente.
They became known as the Allied Powers during that war.
The Central Powers; the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, and the Kingdom of Bulgaria. were originally known as the Triple Alliance, and fought against the Allied Powers that had formed around the Triple Entente.