Xbox One S user? Hi Derek, thanks for your quick reply.
Yes I have updated the software and tried pressing F9 key to confirm my keyboard was working.(Light came on and i confirmed)
Neither when 'KB mode' is flashing and not, the game wasn't recognizing keyboard and mouse.
However, i tried the same thing on the different game BF1(previously i was on Warframe), the keyboard worked perfectly! but no sign from the Mouse yet.(Mouse's LED lights are on from the power connection though)