If you didn't know, the capacity of flash cards doubles about every two years. You can call that Peter's law (in my name :).
In early 2011, Lexar unveiled the first 128GB SD card, then in late 2012 the first 256GB card. SanDisk took the lead in late 2014 with the first 512GB card and now it's doubling the max capacity again.
For now, it's just a prototype - there's no launch or price yet. But the SanDisk Extreme PRO will store a whopping 1TB of data. This comes merely 16 years after their first 64MB (MEGA-byte) SD card.
This card is aimed at the growing number of 4K cameras, 360° cameras for VR and also anticipates the launch of 8K cameras. Well, that may be some way out, but cameras are already moving to 4K @ 60fps, which will eat up even more storage and 6K seems to be on the horizon too.
Again, this card is a prototype and it's not clear how long it will be until SanDisk brings it to market. Also, there's no pricing info, but the 512GB SanDisk SD card launched at $800, so start mentally preparing yourself for that kind of price. Two years later, that card is just $275, though.
Sidenote: If you're wondering why the source link begins with "Western Digital presents", it's because WD recently bought SanDisk for a cool $19 billion. It's a way for the HDD maker to move into flash storage.