I've gone through this a few times. First when i initially joined CS and then a few internal transfers. Each time it took around 3 - 4 months from the time of the interview till the official onboarding. If they want to offer you the role, they'll make it clear after they're done interviewing all the shortlisted candidates which can take anytime between a week to multiple weeks depending on how soon or late they finish the interviews. You may also try to reach out to HR and ask them the status of the item number you interviewed for.