Hey !
Assuming you are talking about the subjects and courses one will be dealing with in their postgraduation in computer science stream, here it goes :
At your starting semesters you will be dealing with core subjects like, Design and analysis of algorithms, Advanced computer architecture, Discrete mathematical structure, VLSI Design, Computer graphics, embedded systems etc. And then in the further semesters you will be having, Computer networks, Operating systems, Advance data base, Compiler design,  Software Engineering, Data mining and warehousing, Mobile computing, cryptography,  soft computing, software testing etc. (Though the names given here may Change with the actual course names you have heard, the content is almost the same). If your query is about the syllabus for the entrance test , then do check the below link for the information.
https://engineering.careers360.com/articles/gate-syllabus-for-computer-science-and-information-technology/amp
Hope this helps
All the best !