All modern laptop batteries (multi-cell ones) do have cell balancing circuitry built inside. There are hundreds of examples on the web, and here is my own, ACER AL10B31 battery, 2P3S configuration, nameplate voltage of 11.1V
This particular battery pack uses BQ8050 battery pack manager with built-in cell balancing:
For more capable cells external FETs can be used, but it doesn't take much to balance internally.
The standard CC-CV charging, however, must be applied externally, which is typically located on laptop mainboard itself.
Many battery packs have protection switch which must be enabled from mainboard via I2C interface. The interface is usually secured and non-disclosed to public, so some people might think that it has a "blown fuse".