Hey there!
There isn't a specific timeline for a background check, but they usually go from 3 to 6 months. In some complex cases, it can take even more than a year.
It depends. If the only country you lived in for more than 6 months is your home country then they won't ask for a PCC. But if you lived in other countries more than 6 months, they will ask you to provide a PCC from each of them.
Background check is the longest stage. Once it's done, you are usually put in a queue for a final decision by a decision maker officer.
Hope this helps.
Cheers!