One feature of the 9.7-Inch iPad Pro is the inclusion of an embedded Apple SIM, rather than a traditional SIM card that is placed inside the iPad’s SIM tray. Unfortunately, Apple’s wording around how the embedded SIM works hasn’t been very clear and it’s led to some confusion and concern that the new iPad Pro has no SIM tray.
To confirm, the 9.7-Inch iPad Pro does have a SIM tray, in addition to the embedded Apple SIM. From the iPad User Guide, available on the iBooks Store:
An Apple SIM card or an embedded Apple SIM is used for your cellular data connection. All iPad Wi-Fi + Cellular models include a SIM card tray. iPad Pro (9.7-inch) Wi-Fi + Cellular also includes an embedded Apple SIM (except in China). If you change carriers or if no SIM card is installed, you may need to install or replace the SIM card.
Embedding the Apple SIM seems like a natural–and smart–progression of this feature from Apple and I’d imagine that all future cellular iPad models (or iPad Pro models, at least) will have this feature.