The character Turk Barrett, played by Rob Morgan, is the only actor who can be seen in all 6 Netflix's Marvel series: Daredevil (2015), Luke Cage (2016), The Defenders (2017), Jessica Jones (2015), Iron Fist (2017), and this series, The Punisher. A lot of the characters can be seen in 1 or 2 out of the 6, but only Turk is in every one of them.
The bar Billy Russo visits is the same bar visited by Ward Meachum in season two of Iron Fist (2017).