QNX was ahead of its time. I think it underpinned most versions of the BlackBerry OS and is used in cars / infotainment systems, but I think they would have made a killing in the IoT space if they had developed in another era.
QNX was only used in BB10, which was only introduced after the fall of BlackBerry's popularity (and, arguably, was part of the reason for their old products stagnating)