They got back together lol after Skyfire got his payback
So basically Megatron told Starscream if he wanted to join him as second in command, he had to kill a closest friend, of course Starscream did it, he didn't want to do it but he did, fearing of punishment if he didn't. He actually didn't kill Skyfire, since Starscream brought Skyfire to earth to kill him, he was frozen, putting Skyfire in a stasis. The Autobots found Skyfire billion years later, fixed him up, and he was an inside personal, and then finally was put to the battle lines. While there he heard a FAMILIAR VOICE (Wonder WHO) when he looked it was his old "Friend" Starscream, Starscream saw him too, and smiled with joy, though Skyfire, having remembered what he did, did not smile, he pointed his Plasma Blaster to Starscreams head. Starscream's smile dropped, and he asked "Why?" Skyfire just said "You shot me.". Skyfire shot Starscream, but missed, hitting his arm. Time skip, the war ended with Megatron locked away, and every Autobot had to meet a Decepticon, Optimus's words, and Skyfire was assigned Starscream, at first they bickered, then Starscream had enough, actually telling him why he did what he did to him (LIKE HE SHOULD HAVE IN THE BEGINNING) and then Skyfire froze, processing this information. Then he finally understood everything, and slowly started to trust Starscream again. (YIPPEE, I am not good at lore bro T-T) Starscream is still a lil insane