If you don't have quarantine configured in your spam filter or malware filter, obviously, there won't be any information here.
If a message that one of your users was supposed to receive never arrived, you can check here to see if it ended up in quarantine by mistake:
Quarantine
Clicking on the message allows you to choose to release it and report it as a false positive, or release it and unblock the sender. If you decide not to take any action, the message will automatically delete out of quarantine, usually in 7-15 days, depending on the reason it was quarantined:
Quarantine details
Note that the quarantine in Exchange Online, ...
