Come to think of it, Netflix's The Punisher will be no different than all other Marvel shows that have aired on Netflix when it comes to Mature Content. Daredevil, Jessica Jones, Luke Cage, Iron Fist. These are all Marvel shows that contain adult-rated content that's never suitable for children.
Jessica Jones contains sexual violence and rape. Daredevil contains graphic violence, blood, gore, and in a few cases decapitation. There are few scenes where partial nudity is shown, including Luke's butt, in many of the Marvel shows on Netflix. And there's a lot of F-bombs and foul language galore in all the shows.
The Punisher will be no different than any other Marvel/Netflix show. But I think the show is going to take a hard-R Rated path and show more of what the other Marvel shows contain. After all Frank Castle, The Punisher, is an ultra-violent grim and gritty guy who struggles to cope with the tragic loss of his family while waging a never ending war against criminals of all types. Blood, gore, murders, nudity, rape, mutilations, extreme violence and abuse, innocent, helpless people getting hurt or killed, bomb explosions, torture, everything that some people especially children find disturbing and traumatizing. Frank has seen it all.
So it'll be no surprise to have The Punisher be a hardcore adult rated show containing explicit content of all kinds straight out of a Punisher Max comic. But if the show contains a harp scene where Frank actually plays the instrument, then that would indeed be a surprise.