The NIST CSF is designed for organizations in the early stages of their cybersecurity development. This is because it serves as a guide to help a company build an information security strategy and establish a basic security posture. ISO 27001 is a better fit for organizations that are more mature and have increased security risk. When pursuing an ISO 27001, your organization likely already has a general cybersecurity program in place but needs more intensive best practices to strengthen your posture and adhere to customer standards.