When does Kim and Kourtney come back on?

First, it's "do," not "does."  Second, if anything, it's Kim and Khloe.  Kourtney has scaled back her appearances on KUWTK significantly.  If you actually watched the show this past season, as your question suggests, you'd know Kourtney's lack of involvement has been a hot-button issue.  Both she and Kris pushing back from letting the production crews film them has led them to be considering cancelling the show, which is how last season ended, leaving the distinct impression that the show might not be back, that that may have been it.