Runoff election for two U.S. senate seats. GA requires each winning candidate to get a minimum of 50% of the votes, and none of the candidates got that in the November election.
IIRC, Perdue (R) was leading Ossoff (D) and Warnock was leading Loeffler (R). Early voting turnouts indicate that both (D) candidates are leading their Republican counterparts.
This is an especially important election. If D wins both seats, then they will have control of the Senate due to the tie-breaker vote from VP Harris. If it's a split (R 1, D1), Republican retains control.