Iso26262 is the safety standard (a slimmed down version of industrial standard by the way).
misra are the coding rules recommended to apply for these standard.
Autosar is an OS definition to make modular SW
There are a number of things under the AUTOSAR umbrella, one of which is a set of C++ coding guidelines, akin to MISRA. This is what the other poster is referring to. Back when I worked at Tesla, we enforced a subset of MISRA rules, and at my current company we enforce a subset of AUTOSAR rules, but use none of the AUTOSAR “platform”.