Democrats will regain control of the US Senate on 1/5/2021 and retain control in 2022.

On 1/5/2021, Democrats win both GA US Senate seats(Ossoff-D and Warnock-D) giving Democrats 50 US Senate seats with VP Harris-D breaking the tie vote.
In 2022, Democrats are likely to win every Democratic held US Senate seat up for re-election in 2022.
37)CA(Padilla-D)
38)HI(Schatz-D)
39)NY(Schumer-D)
40)CT(Blumenthal-D)
41)MD(Van Hollen-D)
42)VT(Leahy-D)
43)WA(Murray-D)
44)OR(Wyden-D)
45)IL(Duckworth-D)
46)CO(Bennet-D)
47)NV(Cortez Masto-D)
48)AZ(Kelly-D)
49)NH(Hassan-D)
50)GA(Warnock-D)
Democrats will increase their majority in the US Senate in 2022 by winning
51)PA(OPEN Toomey-R)Lamb-D