After a breach has been discovered and the immediate threat has been addressed by identifying and removing the threat's access, the next step according to the NIST SP 800-61 Incident Handling Guide is to recover from the threat. This involves restoring systems to normal operation, confirming that the systems are functioning normally, and applying patches or other remediation measures to prevent similar breaches in the future1.
Reference:
Understanding NIST SP 800-61: The Computer Security Incident Handling Guide