Will the Battery of my MacBook Pro 15" 2016 deteriorate if it is plugged in charging all day?
To my knowledge it is more or less a consensus that Li-Ion batteries require regular discharge to keep the electrons moving. This article is one of the most comprehensive I know on the issue. It states that one should avoid low and high temperatures, regular deep discharges, and permanent full charges. The author recommends to use the battery from time to time with shallow discharge cycles.