See the VS 2026 release notes for everything that's changed in the product, the MSVC compiler team's blog post about C++23 Core Language features (yes, they're finally working on C++23!), and as always, the STL Changelog's detailed summary of everything we merged for this release. I take great care to record every single commit that goes into the STL, excluding only README updates and utterly trivial or internal-only changes.

If you have questions or concerns about the product, I can typically get MSVC team members to respond directly here (and I can answer STL questions myself).

Edit: Shortly after I posted this, we also published What's New for C++ Developers in Visual Studio 2026 version 18.0 which covers C++-specific IDE features (and some overlapping mentions of compiler and library changes).