I should be a standard feature for a modern fighter to have the ability to exchange radar information with other systems, it would be a great disadvantage for the F-35 if it couldn't.
It means more then that. What sensor fusion means, or will mean shortly, is that EVERY land, sea, air, space asset will have access to EVERY bit of data every other asset has world wide and a commander will actually have instant ability to assign systems for tasks using data collated by other systems. Anywhere. Any time.
Just look at every single weapons system and data gathering asset being on one grid for war fighters to not only access for a true picture of the battlefield but also use for attack or for a commander to assign a system to attack. This is some real Skynet stuff only needing the A.I. to make it work even faster. Thats why I compare it to the movie Enders Game. It may be only used initially in theater but eventually it will be capable of fighting a global war in minutes and seconds.
Think about it? "Data" is what really helped us win WW2. Data from code breaking, Intelligence, recce planes. And the quicker you got it the better.
So if a F35 runs out of ATA missiles there will be other land, sea, air assets networked into it that will be able to launch in defense of it. Or a million other possibilities because everything is going to be networked together.