Can I give temporary permission to a client?

If the campaign is created on behalf of the agency, the end client may also wish to contribute or see the analytics. In that case you can give the client permission to view a single campaign

Answer - Yes

Invite a new team member to your account.

Assign the Client ifnormation and Position as "Client". Then toggle Access to specific Campaigns and choose the campaign this user will have access to.

Once they log in they can only see this individual campaign and its analytics.