These are users who've decided to cancel their accounts but still have time remaining on the last month of their subscription
Even though these folks have opted-out of your service, they will contribute to your MRR until the end of their subscription periods.
Say Sally signs up on January 15th for a $10 subscription. On February 5th, she decides to cancel. Since she's technically paid through February 15th, we change her status to cancelled, but don't change your MRR. We'll only deduct her $10 from your MRR when she finally does churn on the 15th.
You can see a list of all of your cancelled users on the Customers section (hint: use the filters on the left!)
From an accounting perspective, this methodology aligns more closely with your finance team's revenue numbers and gives you a more accurate picture of your business. From a more practical perspective, these are the users you're most likely to win back or gather valuable product feedback from. Breaking them out on your Activity, Growth and Customers tabs gives you an actionable way to take advantage.