In the begin Mr. Togashi said he only wants to make about 20 volumes for HxH, now it’s already 32 volumes ^^” I think there will be more 1 arc with the completed OT4 and Ryodan after the current arc “Dark Contient”. With all the setup of Dark Contient, it seems to be bigger than Chimera Ant (13 volumes), and the last arc will have many things to do. So it’s one big arc + one big arc = at least 20 volumes more. And with Mr. Togashi’s heath issue, it’s a lot of time to finish the manga.
"For all the readers who like HXH, the author Yoshihiro Togashi is suffering severe backache making it painful for him to work. Therefore, we decide HXH will be on break in WSJ Issue #39&40 (this week and next week). In order to be back in issue #41, Togashi is under treatment now. We hope everyone continues supporting HXH in the future."
Source: Ishuhui and Rio poneglyph from Orojackson