To every ring one can associate its algebraic K-groups, which form a rich invariant and play a role in several areas of mathematics. However, these groups are often difficult to compute. When a ring is constructed from simpler pieces, a descent result provides a way to recover its K-groups from the K-groups of these building blocks. In recent years, techniques from higher algebra and derived algebraic geometry have led to new descent results, with applications extending beyond algebraic K-theory itself. In this talk, I will give an introduction to this circle of ideas and discuss some applications.