Are you looking for schedules or award availability? In many FF programs, award flights cannot be booked more than 330 days in advance of scheduled departure. (This doesn't mean that some or all award inventory will necessarily be released at this time.) However, you might be able to see very tentative schedule information (highly variable with many changes due to COVID-19) farther in advance by searching for tickets to be paid with money.

You can probably find further information on when award availability is likely to open in the fora for airline FF programs whose miles you want to use.