Churn rate
Churn rate is the share of your customers (or revenue) that leaves in a given period. Splitting it into voluntary and involuntary churn is what makes it actionable, because the two have very different fixes.
Involuntary churn is usually recovered with better dunning; voluntary churn is addressed with cancel flows and product work.
churnguardian attributes saved customers to the cancel flow or the recovery sequence so you can see which lever is moving churn.