If i had to guess the "new" means new to xbox so with that in mind, i'm predicting it's either Final Fantasy 16, or less likely FF7 Rebirth. A port has been rumored for ages now and it would also make sense with Xbox and Square buddying up again because the latter is so poorly ran they didn't really have a choice.
Nothing else really makes sense unless it's a bombshell, out of left field type revival/reboot since "legendary japanese franchise" leaves a lot of wiggle room.