You can share your Campaigns with other members of a team you are on, similar to template sharing. Please keep in mind when you share a Campaign, your team members are able to use the content of your Campaign but will not be able to access or manage your recipients. You can share a Campaign by clicking on the Campaign you'd like to share and then select "Share" in the bottom right.
From there, you'll be able to select which team(s) you want to share your campaign with from the team picker.
Any Campaigns submitted by Team Leaders and Team Members will be added to the Campaigns dashboard for use by all team members immediately, though they may need to refresh their inbox.