They say it supports several instruction sets. You might need to fix the operating system to support multiple native instruction sets in a single system (unless you can only use one at a time, but that isn't as useful), and some things might not work well together due to such things as endianness, etc. And then, there is probably many other consideration about working them together too, even if the endianness is the same.
>Production starts in 2023, so we should see actual benchmarks of these chips sometime next year.