In a Facebook post yesterday, G.I. Joe scribe Larry Hama announced that he and the rest of the book’s creative team had been told to suspend work on the series as of issue #275.
The issue, which was scheduled to go on sale in July, was the conclusion of the popular ‘Snake Hunt’ storyline.

Similarly, Teenage Mutant Ninja Turtles writer/artist Sophie Campbell announced on Twitter yesterday that she was told to suspend work on the series as of issue #105.
The issue, which was supposed to be released later this month, would have been the conclusion to Campbell’s first story arc as both writer and artist on the series.

Both creators also confirmed that as far as they know, these are hiatuses for the respective titles and not cancellations.