The Grizzled: At Your Orders!

From BoardGameGeek:

Les Poilus: Aux Ordres! is an expansion for The Grizzled that consists of three elements: Rules for solitaire play. New rules for playing with two players. Mission cards that present players with new challenges that scale in difficulty based on their experience. On this last topic, mission cards come in easy, normal and hard difficulty levels, and based on the experience of the players, you set up a deck of missions. Each round, the mission leader draws two of these cards, then decides which one to attempt. These missions might affect the number of starting cards in a round or allow players not to lose a round due to a specific condition, such as night or rain.