He is horrible with endings, which may be why instead of a real ending, we get a “to be continued” setup for the next film.
There is admittedly some set up for the next film (Snoke recalling Kylo and such) but they are external to the story.
Rey meeting Luke to train with him is the conclusion to the main plot of finding Luke and Rey’s own character arc in the film. There is a “to be continued” in that we know there’s more story that will be told but this is still 100% an ending to the story that the film is telling.