The NFL has informed teams that the 2021 salary cap will be no lower than $180 million, a slight increase from last year's previous agreement between the league and the NFL Players Association.
https://www.espn.com/nfl/story/_/id/30923265/nfl-increases-2021-salary-cap-minimum-180-million
The final 2021 cap figure, the memo says, "will be set following review of the final 2020 revenue figure and other audit and accounting adjustments." The new league year and free agency are scheduled to begin March 17.
Sources familiar with the negotiations told ESPN that the final number is likely to be between $180 million and $185 million, though almost certainly on the lower end of that range.