http://www.pcgamer.com/assassins-creed-origins-will-get-a-free-update-alongside-its-first-expansion-this-month/

The first DLC for Assassin's Creed Origins (our vote for best open world game of 2017) is due out this month. Called The Hidden Ones, the expansion will add a new region to the already massive Egypt map, and today Ubisoft announced a few extras that will arrive alongside it:

That's the free stuff. As for the expansion itself, which is included in the Season Pass (I don't yet see a price listed to buy it alone), it features Bayek fighting the Romans in the new map region as part of events that take place years after the story of Origins. The level cap will jump from 40 to 45, leaving you room to become an even more deadly assassin.