With reference to comics. Connor Hawke popularly known as the second Green arrow -one of the greatest martial artists in the DC Universe and an excellent archer. Oliver Queen is his Father and his mother is a woman named Moonday Hawke. Oliver Queen abandoned him at an early age because he was not yet ready to be a father, but they rekindled their relationship later on in life and Connor forgave him. Connor had a volatile temper and had often fought back while his mother was unsure what to do with him. Because of Connor's problems in school, Connor's mother decided to sign the papers allowing Connor to attend the same monastery that Oliver fled to for a brief time years before called the Ashram Monastery in the Napa Valley. Master Jansen, the same monk who helped Oliver, raised Connor for the next five years in the Ashram. Later, after a troubled time in his career as Green Arrow, Oliver Queen decided to leave Seattle to shed himself and headed to the Ashram Monastery on a journey he once had gone before over a decade ago. Surprisingly, Oliver found was a young man named Connor Hawke who, unknown to Oliver at the time, was his son. During his six month stay, Oliver taught Connor aspects of himself, his beliefs, and his thoughts on the role needed to be the "hero" Green Arrow. Connor hawke has also been a member of Team Arrow and the Justice League.
This gives two major possibilities.
1. Featuring of this so called "Ashram" in the series.
2. Bringing Connor Hawke "The Second Green Arrow" to the series. For which we already have seen some clues.
From earlier episodes of season 2. There was hint about Oliver queen's son. However this lady (not yet named in the series)was paid by Oliver's mother for hiding the truth from Oliver.
From recent Flash vs arrow crossover episode. Oliver meets her in Central city.They have a little conversation. Even so she doesn't talk about their son. After Oliver departs she gets a call from their son.