ONEST, Thank you for posting in the Intel® Communities Support.
In reference to your inquiry, just to let you know, the T-case temperature is the maximum temperature allowed at the processor Integrated Heat Spreader (IHS).
As general information, the mobile/embedded processors, such as the Intel® Core™ i7-8665UE, since they were integrated by a specific OEM (Original Equipment Manufacturer) they do not show the T-case temperature, they show, as you mentioned, the T-junction temperature:
https://ark.intel.com/content/www/us/en/ark/products/193554/intel-core-i7-8665ue-processor-8m-cache-up-to-4-40-ghz.html
The Desktop processors, for example, the Intel® Core™ i7-6700, do show the T-case temperature since they are normally assembled by the users that build their own computers:
https://ark.intel.com/content/www/us/en/ark/products/88196/intel-core-i76700-processor-8m-cache-up-to-4-00-ghz.html
Still, we will do further research on this matter in order to confirm if the T-case temperature value is available for your Intel® Processor, as soon as I get any updates, I will post all the details on this thread.
Any questions, please let me know.
Regards,
Albert R.
Intel Customer Support Technician
