C:\Program Files (x86)\Heroes of the Storm\Support\BlizzardBrowser\BlizzardBrowser.exe get reported and quarantined by McAfee real time scan when it is run.
This does not affect how the games play but it does cause the updater to replace the file the before you launch the game again, for it to only be quarantined again.
This only started happening with this weeks update to Heros of the Storm, so might because of new version or it might be due to a new virus definition update.
McAfee identifies the Threat Name as “Real Protect-LSI6F3D84CC34B8”
McAfee VirusScan Version 22.1
Build 22.1.145
Engine Version 3556.0
Engine Creation Date 12/12/2018
This is probably a false positive by McAfee