Ulink2 is working fine in Keil4.73 and is able to program TLE9867 device but in Keil5.20 with firmware V2.03 of Ulink2 it is not able to program TLE9879 Infineon MCU. in keil4.73 even with firmware V2.03 of Ulink2 , one can program TLE9867. so conclusion is that Keil5 is not supporting programming of TLE9867 device with Ulink2.
Moreover, are you sure you are using an official ULINK2 from keil (not the copied version from ebay)?
Yes, I purchase a licence version of Ulink2 from Keil. no pirated copy