Rise of the Tomb Raider still doesn't have a solid release date on the PC, but what it does (or will) have is microtransactions. Yes, we're delighted too. Creative Director Noah Hughes explained on the Xbox Wire that players will be able to use "Expedition Cards" to gain various modifiers or advantages, and while those cards can be acquired with credits earned in the game, they'll also be sold for real money.
"Expedition Cards offer hundreds of ways to customize your Rise of the Tomb Raider experience. You can also set up challenges for your friends to see if they can beat your scores with the same card setup," Hughes said. "We’ll have about 300 cards available at launch, and more will be added in the weeks that follow."
Cards will come in two types: Foil, which provides the "strongest or strangest" effects and have unlimited uses, and the less powerful Common, which can be used only once. Some of the cards are "humorous," such as one that enables Big Head Mode, while others have a more meaningful impact on gameplay: The "Bullet Resistance" card, for instance, which confers (as you may have already put together) bonus resistance to gunfire.
A Rise of the Tomb Raider season pass will also be offered, with three "major releases," which I take to mean DLC—Endurance Mode, Baba Yaga: The Temple of the Witch, and Cold Darkness Awakened—on tap along with "a steady stream of outfits, weapons, and Expedition Cards beginning on day one and continuing over four months." The season pass will sell for $30 over the $60 price for the standard release of the game.
Bear in mind that this is all specific to the Xbox editions of the game, since those are the only ones that have an actual release date at this point. I asked Square Enix if all of the above will apply to the PC version as well and was told only that more details will be revealed "soon," but in the absence of any information to the contrary it's reasonable to assume that Expedition Cards, and the season pass, will be an across-the-board proposition.