Can someone shed some light on the differences between a VMS and a BMS and how they relate to eachother. Say for example a VMS like iNEX from IDIS is used in a system, how would that relate to a BMS? Also, the term BIS was brought up and I'd like to understand it a bit better. When I googled BIS, I think I understood that it's just a branded BMS made by Bosch, is this correct?

VMSes and BMSes are typically completely different 'animals' (one manages video, the other buildings - like HVAC, lighting, etc.)

A VMS might be integrated with a BMS but it's not that common. More likely a VMS is integrated into a PSIM because that has more to do with security.

Yes, BIS is Bosch's version of a BMS, which does integrate with Bosch VMS!