The latest trailer for Civilzation 6 shows off the abilities you can call upon when playing as Greece.
The Greeks are led by Pericles, an influencial Greek figure who served as general of Athens during the 'Golden Age' between the Persian and Peloponnesian wars.
Playing as Greece, your unique ability is Plato's Republic, which gives you an extra wildcard slot. The hoplites, your unique unit, grow stronger when they are placed adjacent to other hoplite units, and the Acropolis gets high adjacent bonuses from being next disticts, although it must be built on a hill.
Greece starts very strong from the beginning on a game, so you'll want to take advantage of that in the early turns.
Civilization 6 released for PC on October 21.