When I moved in-house many years ago, it was unthinkable that law firms would be dispensing anything other than legal advice to general counsel and their teams. In fact there was a tendency to indulge in some propaganda to undermine rather than support in-house teams. Nowadays law firms and other professional service providers, especially in the US and the UK, are looking for ways in which they can provide additional support or at least demonstrate that they would like to.
Some put a lot of effort into producing interesting material. A good example of this is the survey and report ‘The Influential GC’ produced by Nabarro.
There are others who fail to disguise shameless marketing or client flattery. No links for that!