Xiaomi Mi A2 is expected to share its hardware with Xiaomi Mi 6X but run stock Android, instead of the in-house MIUI. That would mean a Qualcomm Snapdragon 660 chipset coupled with 4GB or 6 GB RAM.
The dual camera on the back is 12 MP + 20 MP and comes with AI enhancements, although they come from MIUI and not the Android itself, so it would be interesting to see if Xiaomi implements its over 200 scene recognition modes in a device with a pure OS.