The political party the wins the state at the Presidential Level will also win at Senate Level.

Biden states are going to win-
AZ(Gallego-D)
CA(Schiff-D or Porter-D)
CT(Murphy-D)
DE(Blunt Rochester-D)
HI(Hirono-D)
ME(King-I is the de facto D)
MD(Alsobrooks-D)
MA(Warren-D)
MI(Slotkin-D)
MN(Klobuchar-D)
NV(Rosen-D)
NJ(Kim-D)
NM(Heinrich-D)
NY(Gillibrand-D)
PA(Casey-D)
RI(Whitehouse-D)
VT(Sanders-I is the de facto D)
VA(Kaine-D)
WA(Cantwell-D)
WI(Baldwin-D)

This is what happened in 2016. Democrats will lose US Senate Elections in MT,OH,and WV.

In 2020 the states that went for Trump and the Democratic US Senate nominee are-zero.

Trump- Republican US Senate nominee.
AL
AK
AR
ID
IA
KS
KY
LA
MS
MT
NE
NC
OK
SC
SD
TN
TX
WV
WY
Biden Democratic US Senate nominee.
AZ
CO
DE
Both GA seats
IL
MA
MI
MN
NH
NJ
NM
OR
RI
VA
Biden Republican US Senate nominee
ME

Democrats will hold onto battleground US Senate seats in AZ,MI,NV,PA,and WI.
Democrats will need a weak Republican opponent in MT and OH.