Apple appears to be building LinkedIn integration into iOS 7, though the feature is not active in the beta of iOS 7 that was released to developers last week. It is said to look similar to the social network integration that iOS currently sports for Facebook and Twitter.
Apple supposedly included Facebook integration in an early build of iOS 5, but it didn't make it into the final build because of failed negotiations between the two companies. Facebook integration was built into iOS 6.
9to5Mac, which originally reported the story, says iOS 7 users will be able to post content directly to LinkedIn via a share sheet. Apple has already announced LinkedIn integration for OS X Mavericks, so it would make sense to see similar integration in iOS 7.