(written from a Production point of view)
CTV is a Canadian television network launched in 1961, and owned by BCE Inc., formerly known as Bell Canada Enterprises Inc.
On 6 September 1966, CTV became the very first network in the world to air Star Trek: The Original Series, beginning with "The Man Trap", beating NBC to the punch when it started airing the series in the United States two days later with the same episode. 
In Canada, on 25 September 2017 "The Vulcan Hello", episode 1 of Star Trek: Discovery, initially aired on CTV, while "Battle at the Binary Stars" aired on Space. On 23 September 2017, the network had aired Star Trek, promoting Discovery during the commercial breaks by airing clips of the show and interviews. Subsequent episodes of Discovery have been shown in first run on Space (in English) and Z (in French), its sister cable channels. The episodes have been aired concurrently with CBS All Access' airings in the US, beginning with episode two in September 2017.