The function to just bring outside air when it makes sense is an extremely common feature in commercial HVAC systems - it’s called ‘night purge’.
Most of these systems have a damper that the system can use to choose how much fresh air is used or how much return air is recirculated so it’s not difficult to use that to just put fresh air in directly with no cooling or heating. Even systems with heat or energy recovery will often have a bypass damper.
You need the humidity to be in the right range as well as the temperature, but it can save a lot of energy!
Most of these systems have a damper that the system can use to choose how much fresh air is used or how much return air is recirculated so it’s not difficult to use that to just put fresh air in directly with no cooling or heating. Even systems with heat or energy recovery will often have a bypass damper.
You need the humidity to be in the right range as well as the temperature, but it can save a lot of energy!