HBO scrapped a Braavos set Game of Thrones spin-off but A Song of Ice and Fire author George R.R. Martin wants to write it proper once upcoming novel The Winds of Winter is finished.
Second, it's clear HBO will continue to make Game of Thrones content for many years to come. While I would love for George to write it and HBO to eventually adapt it, I'm confident we'll get it in one form or another someday.