did the ISV Layer Runtime license Code is different than the ISV Development License which open the ISV layer ?
Yes, ISV Layer Runtime license code is given by the ISV partner so that you can run the Solution provided by the ISV partner.
ISV layer license is provided by Microsoft so that you can develop ISV solutions for Dynamics AX
to get ISV layer license you need to be Independent Software Vendor partner of Microsoft
there are some requirements related to that.
Please check further with Microsoft site