Dark Energy (and modified gravity) in two body problem: theoretical implications and observational constraints

General Theory of Relativity needs at least one modification - the Cosmological Constant. Yet there are possibilities for other modified theories of gravity to explain the accelerated expansion. In this talk I'm going to discuss the impact of Modified Gravity on the two-body problem. In particular, with the latest observational constraints from the galactic center, binary pulsars and the Milky and Andromeda dynamics and forecast for future measurements.