Big "maybe" on this, but I think that Oxenfree II: Lost Signals could possibly include references to the game Oxenfree (or at least be inspired by it). I mean, the title of the game includes the word "oxenfree" which seems awfully similar to "Oxenfree." Though, it feels like that could be quite the stretch for the developers, so it might just be a coincidence. In the trailer for the game, it showcases a character using a radio to tune into different frequencies to open a triangle-shaped gate/portal. I've only played the game 20 times so I'm not entirely sure, but I know the mechanic was used at least once in Oxenfree. However, other games might be better known for it, so it's best to take the connection with a grain of salt. Both the game's description and the trailer use the name "Camena" to refer to the setting of the game. That name might be the same as the name of the hometown of the main characters in Oxenfree, but I'm too lazy to look that up right now. Even if it is the same, it's still a super cool name, so it might just be another coincidence.