The IAAF is adding a mixed gender 2x2x200 relay and also mixed shuttle hurdles at the upcoming World Relays. They’re getting rid of the 4x800 for this.
I personally believe that this isn’t a good move. The 4x8 is one of the most exciting races to watch. If they’re going to mix the genders, you might as well just run the usual race. Overall, it’s just a bad move for the sport. If it ain’t broke, don’t fix it.