[EvanAnderson]

No. Your employer can't MITM your personal email session if you don't trust their MITM proxy's CA.

[notatoad]

if your employer controls your work computer, they can set it to trust their MITM CA.

cert pinning means they can't do that unless they're also modifying yoru email client binaries.

[Thorrez]

It depends on your email client. If your email client is Chrome, then the pinning won't help you at all.

>Chrome does not perform pin validation when the certificate chain chains up to a private trust anchor.

https://chromium.googlesource.com/chromium/src/+/refs/heads/...