In Uncharted 4 Multiplayer, you can complete small gameplay challenges to earn Relics which can then be spent as currency in the Uncharted 4 Multiplayer Store. Challenges are given at random, three at a time, and can only be completed in matchmaking. Relics are awarded upon challenge completion, with the amount depending on the difficulty level. Each day, one of the completed challenges will be replaced with a new task.
If you don’t like any of your challenges, you can replace it in the “Challenges” menu for the price of 50 Relics each. Three challenges will be called at random and you’ll be able to choose a new challenge from those. Some examples of challenges you might encounter are picking up treasure, using certain long guns and pistols, calling in sidekicks, and performing special melee moves.