IBM offers a free set of courses here: https://ibmzxplore.influitive.com https://ibmzxplore.influitive.com. I played around with it a few months ago. As far a

IBM offers a free set of courses here: https://ibmzxplore.influitive.com https://ibmzxplore.influitive.com. I played around with it a few months ago. As far as I know it's still available. It doesn't cover COBOL in great depth but does touch on various pieces of the zOS ecosystem and gives you some access to a real mainframe. There's also this COBOL course: https://github.com/openmainframeproject/cobol-programming-course https://github.com/openmainframeproject/cobol-programming-co... I haven't tried the later and I'm not entirely clear on how you get access to a mainframe environment for it.