expression
Polite expression of uncertainty, attached after a plain-form clause, adjective, or noun phrase. It is the polite counterpart of かもしれない and is common in careful conversation and writing.
See also: かも知れない (かもしれない)
明日は雨かもしれません。
It may rain tomorrow.
電車が遅れるかもしれません。
The train may be delayed.
彼はもう帰ったかもしれません。
He may have already gone home.