Let's say you have a campaign scheduled for a certain date and you wish to pause it now so that it doesn't send on the set date.
Currently, there is no option to pause a scheduled campaign. That said, you have 2 options depending on your use case.
You can edit the scheduled campaign and set a date far in the future. That essentially means the campaign won't go anytime soon, giving you a practical pause.
If the campaign is not something you want to go ahead with at all, you can also delete the campaign.
"Edit" and "Delete" options are both available from the campaign listing.