What expected directional variation in the CMB must cosmologists subtract due to our local motion?

Answer

Dipole anisotropy

The Earth's orbital motion, the Sun's orbit, and the Milky Way's movement create a predictable dipole anisotropy—a hot spot in the direction of motion and a cold spot opposite—which is kinematic and must be removed.

What expected directional variation in the CMB must cosmologists subtract due to our local motion?
universeobservationcosmologydirectionisotropy