It depends upon the antenna and the box you have.
Basically - Dish uses three satellites in the west, two in the east. If the antenna has one LNB, with is the case with almost all dome type dishes - it can only 'see' one satellite at a time. Two different TVs can watch different channels from Dish, IF they are on the same satellite. If they are on different satellites, no can do.
If you have a three LNB antenna - it can 'see' all three western satellites at the same time, and different channels on different satellites can be viewed at the same time.
Box - you pay per box for your service. If you have two TVs, and the cheaper boxes, you need one box for each TV. Or you can buy a more expensive box with two tuners so that it can display two different channels on different TVs at the same time. The Sling/ Hopper boxes seem to be the best, but we have an older single channel box. (Note - you need a two tuner box to be able to record one channel on DVR and watch a different channel at the same time. Wife wants me to buy one.)
One other point about Dish. In Nov 2018, HBO and it's associated channels were removed from Dish. This was about 10 months after HBO was acquired by AT&T. Another company which AT&T owns is Direct TV. Make up your own mind as to why the two companies - Dish and HBO/AT&T/DirectTV were unable to conclude a new agreement in 2018.