It's "up to" 8MB.  The first block was about 2MB and the rest have
been much much smaller:  https://cash.coin.dance/blocks#blockDetails

Not only that the time between blocks is very long (hours), but every 6
blocks the mining difficulty is adjusted. The target is to have Bitcoin
cash blocks mined approximately every 10 minutes as with Bitcoin.
Initially then, the blocks will be even smaller.