Depends on your product and audience, but here are few things you can consider,
1. Mandatory feedback options to identify the "Why"
2. Price - Give offers/value to the subscription during the churn process
3. Product - Priority support options through a CSM/ optimisation call, Get feedback on the UX.
4. Competition - Identify who you're losing the most to and check their value proposition to improve your process/products
5. Re-look at the churn process
Hope this helps!