CFexpress Type B cards are more affordable and have a higher capacity than their equivalent XQD cards
About a year ago, Nikon released a firmware update for the Z 6 and Z 7 mirrorless cameras, which introduced support for CFexpress memory cards that were not originally available on these models. Support was possible because CFexpress B format memory cards are identical in form factor to XQD cards, originally designed for Nikon Z 6 and Z 7 cameras. Then the manufacturer promised to add support for CFexpress Type B cards in D500, D850, and D5, also equipped with XQD card slots. In keeping with its promise, Nikon has already made available the relevant updates, albeit so far only on the Japanese site.
Added support for CFexpress Type B cards in Nikon D500, D850, and D5 cameras
Nikon D500 is version 1.30, for Nikon D850, it is version 1.20, and for Nikon D5, it is version 1.40. Besides adding support for CFexpress Type B, they also fix some bugs found in previous versions.