
XQD cards were manufactured by Lexar and Sony, until June, 2017, when Lexar announced that they were discontinuing their retail memory card business, including XQD memory cards. Since then, only Sony has been manufacturing XQD cards.
The XQD card was created for high-definition camcorders and high resolution digital cameras, as it offered considerably better performance than Compact Flash memory cards, even CFast cards.
While Nikon bet on XQD cards, their competitors bet on CFast memory cards. Today it's clear that Nikon won their bet. Frankly, based on the different cards' specifications, I don't understand how CFast supporters thought they'd win their bet.