Hi,
You're not giving enough details about your architecture, iframing is directly depending on your network configuration. Are you using a common domain, or completely different URLs ? Are you deploying on prem, or in Mendix Cloud.
However, here are some useful information about iframing.
If you are fully on prem, you should have a look to this module : Mendix Marketplace - iFrame Mendix in Teamcenter AWC
If either Teamcenter or Mendix is in the cloud, you should read :
Below are some screenshots related to what you will read with above links.
SameSite (requires an HTTPS connection)
com.mendix.core.SameSiteCookies = None
See pictures in Studio Pro and in Mendix Cloud console.
If you don't have a common domain,