Comcast has already started offering access to Xfinity TV without a set-top box, but your choice of TVs has been limited -- we hope you like Samsung. However, you're about to have a wider selection. LG's 2017 and 2018 televisions will have access to Xfinity TV directly through the set once a beta app arrives in early 2018. You'll get the same X1 guide as well as access to live and on-demand programming (including your cloud DVR), just without the hassle and cost of extra equipment. Logically, it'll start with 2017 4K sets before moving to the as yet unannounced 2018 hardware.
It's no secret as to why Comcast is eager to get rid of the box requirement despite the profit it can make from leasing gear to customers. The reduced service costs could deter cord-cutters put off by all the extra fees that go into cable. Also, this helps lock customers in. If you know your set has built-in Xfinity TV support but would (usually) need extra gear to tune into a rival like DirecTV, which service would you prefer? Whatever Comcast loses in service fees it makes up for with more subscribers.