Three months ago, Microsoft fully unveiled the Surface Hub 2S, promising that it will arrive in June for $8,999. It's a modular collaboration computer though, and the different pieces include the display, the compute unit, the stand, the battery, the pen, and the camera.
Priced at $169.99 and $219.99, respectively, you can't buy them. There's just a message on the listings that says "Call to order". This isn't surprising, since that's the same thing that it says on the Surface Hub 2S page. These are business products, so sales come through the proper channels.
There's not much of a description for the Surface Hub 2 Pen, only saying that it's "so responsive it feels like ink is flowing from the pen tip." If $169.99 sounds like a bit much though, any N-Trig pen should work with the Surface Hub 2. The listing for the Camera notes that it records in 4K, and it has a "full field of view that captures the room in lifelike detail for remote meeting participants."
One of each is included with the Surface Hub 2S. If you want to buy one, you can call 866-425-4709 between 6am and 6pm Pacific Time, Monday through Friday.