The thing is, Harrison rejected almost everything Dexter was about in the finale. But Harrison did stand by the code, which he used to justify killing his dad (because Dexter killed Sergeant Logan, who was innocent). In a way, we believe Harrison still wants to follow his father’s advice, but he’s going to craft his own path in doing so. We think Harrison goes to California, away from any reminders of his serial killer father, so he can start anew.

Source: https://www.distractify.com/p/where-will-harrison-go-dexter-new-blood