2K has currently a winter sale, which includes big discounts for Civ4, Civ5, Civ:BE, Civ6 and Civ7! This also includes the Civ7 DLCs (besides Tides Of Power, which is currently free).
For people who already have all the civ games, there are also discounts for Marvel Midnight Suns, as well as XCOM 1 and 2 (among other, less interesting games 😉 ).
The sale runs until January 5, check it out here.