Another possibility for a spin-off of an established property, Journey Into Mystery was of course the name of the comic that saw Thor's debut (something that was nodded to in Thor's first movie), and whose iteration of Loki played a major part in Tom Hiddleston's performance as Loki in the MCU. The Evidence: Again, it partly comes down to filed trademarks, as Marvel included Journey Into Mystery in their December filing. Since Christopher Yost and Craig Kyle were announced as the writers for Thor 3's not long after those trademarks were filed, it seems possible that Journey Into Mystery might simply be the title chosen for the threequel, as well as one of the many storylines forming the foundation for the narrative. But, there's also the possibility that Marvel have paid attention to the fandom that actively petitioned to see a stand-alone movie for Loki - something that was apparently talked about tentatively last year at Marvel Entertainment. It would certainly fit, with the possibility to see an expanded cast of characters without Thor.
