For licensing purposes, Gurobi always aims to count physical cores. To this end, it queries the operating system for the number of physical and logical cores.
Gurobi licenses always contain the (maximal) number of (physical) cores for which they are valid. (For reasons of backward-compatibility, they also contain the number of sockets if it is greater than 1.)
On Virtual Machines
On virtual machines, the number of physical cores is more difficult to obtain since VMs typically hide the difference between physical and logical cores.
In a properly configured VM with hyper-threading, a total number of 16 logical cores would be counted as 8 physical cores. It is always possible to download and install Gurobi and use the "grbprobe" utility to check how many physical cores are measured by Gurobi.
On Gurobi Instant Cloud
AWS and Azure machine specifications in the Cloud Manager show the number of physical cores.
Note that the specifications on the AWS and Azure website may list logical cores instead (e.g. as "vCPU" on AWS). For all available AWS instance types on Instant Cloud, the number of physical cores is half the number of logical cores. However, there are machines on Azure (such as the H-series, e.g. H16m) where hyper-threading is turned off, and physical cores are equal to logical cores.