What are the security challenges you foresee with wide adoption of 5g?

https://techcrunch.com/2019/10/09/european-risk-report-flags-5g-security-challenges/

Nothing specifically new is added to risks in 5G versus 4G. Just the speed of the mobile connection is similar to a fiber cable connection.

The number of IOT connected devices will increase a lot. The security for this kind of devices is too low. Many chinese vendors have a very low security standard: Predefined passwords, open ports, backdoors. You can review the number of IOT devices exposed in a browser like Shodan