The Winter Update adds the new "Earth" map and a bunch of balance tweaks, while the paid Poland and Viking DLC packs add new civilizations and scenarios.
There's a bunch of new content for Civilization VI players launching today as part of the game's Winter Update. Freebies that all players can enjoy include the new "Earth" map option (which as you would assume replicates our own planet Earth as a Civ VI map), the "Alert" action for units (which puts them to sleep until they see an enemy unit) and a plethora of bug fixes and visual upgrades. If you've got the dosh to spend on premium DLC, two $4.99 packs also launched today: the Poland Civilization and Scenario Pack and the Vikings Scenario Pack.
The Poland pack includes the complete Polish civilization with it's leader Jadwiga, the Winged Hussar unique Unit, and the Sukiennice unique Building. It also adds the "Jadwiga's Legacy" scenario, in which you will play as Poland as it defends itself from the Teutonic Knights and Ottoman Turks.
The Vikings pack doesn't contain a new civilization, but does add six new City-States, three new Natural Wonders and the "Vikings, Traders, and Raiders!" scenario, in which you play as Harald Hardrada of Norway, King Canute of the Danes, or Olof Skotkonung of Sweden, and attempt to conquer England, Paris and the Mediterranean.