Thanos writer Donny Cates has confirmed that the series will end with April's #18.
"Thanos #18 will, in fact, be [Geoff Shaw] and I's final issue, and the final issue of the Thanos run for the time being," Cates said on Twitter. "I want to emphasize that this was our call, and it serves a higher story-related reason. Expect to see big Thanos stuff this summer. And thank you all so much."
The solicitation for April 11's Thanos #18 noted the issue at the end of Cates and artist Geoff Shaw's story, and no issues were solicited for May or June.
Cates also reassured readers that fan favorite characters wouldn't necessarily be going away, saying, "As for the fate of certain characters, be sure to grab Thanos Annual #1 and the Cosmic Ghost Rider series as well! Those things all count and are very critical to the future of both characters!"
And as for the future of Cates' Marvel work - and his partnership with Geoff Shaw - the writer says news is coming on both fronts.
"You’re very welcome. And yes, kudos to [Marvel, C.B. Cebulski, Axel Alonso, and Jordan D. White] for letting us tell the story we wanted, and for letting us end it on our terms. I can’t thank them enough for the incredible support. Much more to come from yours truly and the House Of Ideas!," Cates said, following that up with "Geoff Shaw and I have a crazy new thing planned next."