Iran has several MBT programs so it is hardly surprising that North Korea, a country which has its own ballistic missile program, can afford to design their own tanks too. I wouldn't be surprised if a lot of things are placeholders in the design, sure, but typically when North Korea shows a system in a parade it means it is a program of record and even if they show a mockup this year it will enter service eventually.
The tank transmission and chassis seem brand new to me and working. I suspect the turret is mostly a mockup. The tank seems to have both Chinese and Russian design influence. I am kind of surprised at that clone of the US's putrid MGS Stryker variant though. Not to mention the US style cammo.
There are just so many systems I have never seem before it is quite incredible to be honest. I think since the ICBM and nuclear program have already finished R&D as a priority development they could now switch all those resources to conventional forces and those are a lot cheaper to get and easier to get components for in the first place.