GPS has to account for Einstein’s relativity.
Without corrections, GPS satellite clocks would gain about 38 microseconds a day relative to clocks on Earth.
A GPS satellite’s speed makes its clock run slightly slower relative to an Earthbound clock. Weaker gravity at its orbital altitude has a stronger effect in the other direction.
Together, those effects would put the satellite clock ahead by about 38 microseconds per day. GPS accounts for the difference because it uses precise timing to calculate where you are.