.. かもしらない

Added to the end of a sentence “ka mo shiranai” turns whatever you just said into a “perhaps”.

So if you say, “he is coming now” : 彼が今くる “kare ga ima kuru”

and then add “ka mo shiranai” : 彼が今くるかもしらない　”kare ga ima kuru ka mo shiranai”

then you can change the meaning to “he is probably coming now” or “he might be coming now”