Currently Tableau Server is only available on Windows OS
However, a version for Linux is in the works and will be available soon
All the best
Theoretically you could install Server on a virtual machine on your mac if you have a copy of windows and can give it enough CPUs and RAM.
What is the purpose for getting it installed on the Mac?
I've a mac as well. I tried to install Server using Pararells but with only 8GB RAM it can not be installed (Minimim Mac RAM is 16Gb as yo need assign min 8GB to VM for Server). So...I installed it on Azure in 30 minutes and I manage it with Microsoft Remote Desktop without problems. In this case remember to open port 80 on Firewall...