Membership pro 2 -- pay and not leave site

Is there a guide that specifies which payment gateways can be used with the membership plugin that do not leave the site at checkout? I registered for a Paypal business account and just found out that I can't use it with this plugin without going to the Paypal site.

Do you plan to add Paypal pro in the future? Which gateways can I use right now to keep users on my site?