Marketing Cloud unsubscribe has 2 settings:
- Unsubscribe subscribers from all Business Units
- Unsubscribe subscribers from this specific BU only.
Assuming option 1 is in place the unsubscribe is captured in
_subscribers and spans across all BUS.
to find this you can run the query
status = 'unsubscribed'
However if option 2 is in place, unsubscribes specific to that BU are captured in a different data view:
The query you would then use is:
businessunitid = 'yourbusinessunitid'
This will pull unsubscribes that happened as a result of the subscriber unsubbing from a specific BU only because option 2 was in place
businessunitunsubscribes is the data view used to understand unsubscribes from a specific BU when the unsubscribe from this BU only feature is enabled