The Republican National Committee has set strict rules for primary season presidential debates. Here is the schedule of officially-sanctioned debates. The first one is in Cleveland on August 15, less than four months away. It will be broadcast on Fox News.
The Republican Party will probably have a problem choosing which candidates are to be invited. This article shows that there are now 19 Republican candidates who have the political experience, and/or the support, to be considered “bona fide” candidates. Thanks to Thomas Jones for that link.