The infantry fighting vehicle BTR-K Kamysh and its anti-aircraft cousin ZSU-39 Tigris share the same vehicle platform. Developed by Russia with a pinch of undeniable inspiration from Israeli IFVs, they serve in the CSAT army as a prime example of a leveling of the technology field with the West. The Tigris is fitted with a 35mm autocannon and 4 Titan AA missiles.
Like the Kamysh, the chassis of the Tigris is likely to have been based on a combination of two real-world tracked vehicles; the "BMPT" and the "BTR-T" IFVs.
The gun turret itself however, is a shared design that is also used by the IFV-6a. It is based on the real-world "Marksman" anti-aircraft gun system.
The ZSU acronym (Russian: Zenitnaia Samokhodnaia Ustinovka) is a designation used for Russian gun-based, self-propelled Anti-Aircraft vehicles.
However, like its parent vehicle the Kamysh, the Tigris' designation is somewhat of a misnomer; ZSU vehicles typically follow a specific naming convention. An example of this would be the real-world "ZSU-23-4 Shilka"; ZSU designates that it is a SPAAG, followed by its calibre being 23mm (-23), and having 4 cannons on the system (-4).
The Tigris' name would suggest that it fires 39mm shells despite the in-game cannons actually being chambered to fire 35mm shells. Therefore, the correct designation for it would actually be ZSU-35-2 Tigris.