This sounds really dumb, but for the life of me I cannot find any Windows 10 boot camp drivers. With Google all I can find to download from Apple is Windows 7 and 8. Does anyone know where the recent iMac drivers are for Windows 10?
Here's a link that has various boot camp drivers
I don't know if it includes the 2015 iMac, if I were a betting man, I'd say Apple didn't develop any boot camp windows 7 or 8 drivers for the 2015 iMac since Windows 10 was current. Apple tends to only support the latest version of an operating system.
To download the latest set of drivers open up the bootcamp assistant and then select the action menu
View attachment 680199
I thought you were looking for windows 7 or 8 for the iMac, sorry for the confusion.