Sorry if that answer seemed blunt but to be more in detail (assuming this info is allowed to be shared since it's in the Discord's Oddball FAQs) Project Oddball continues the Story of Halo 3 ODST and Halo New Blood. It will be available for Custom Edition just like SPV3 although it won't be using any content from it and it won't play like SPV3. Despite that, it will use the same species but will include Engineers and Drones. The team is currently hoping to release it in time for Halo 3 ODST's 10th Anniversary. Due to that, I doubt we would see any campaign expansions for SPV3, especially since the beta for None Left Behind is cancelled. Although I think there will be a patch at some point, it's mostly minor fixes and stability.