The nature of Marvel Editor-In-Chief Axel Alonso's "2" teaser with the Thing has seemingly been revealed - Marvel Two-In-One is being revived as part of Marvel Legacy, featuring Thing and Human Torch.
The cover, credited by Marvel to Edgar Delgado, homages Fantastic Four #159 by Rich Buckler and Joe Sinnott. As with most other Legacy homages, no creative team or issue number is attached to the image. Note Steve Rogers in his classic Captain America look on the new cover.
The last issue of Marvel Two-In-One was 1983's #100.
It remains to be seen in this precludes a full-on return of the Fantastic Four.