They added Endeavour last year -- a series about young Morse getting started on the force -- with one movie to see how it went. ("Endeavour" is Morse's first name, which was never revealed until the middle of the final season.) The movie was pretty good, and obviously did well-enough for them to bring it back.
There was were a couple of nice touches in that initial movie.
For a small role as an expert that young Morse interviews, they hired Abigail Thaw, John Thaw's daughter, to play it. The scene was very nice, but they added a few nice touches in the dialogue. As Morse leaves, he pauses a moment and looks back at her a somewhat confused look, and asks, "Have we met??" She whimsically smiles, as she shakes her head no, and then says, "Perhaps in another life."
That was last year. In the new, second episode this year, they brought Abigail Thaw back, but in a different role, one that clearly is intended to be a small, but recurring role, as a newspaper reporter.
Also, near the very end of that initial episode, young Morse is asked to drive a Jaguar, the car which later became the older character's signature vehicle in the original series. The young Morse (played very well by Shaun Evans) looks in the rearview mirror, and his image there fades to John Thaw as old Morse. In this very short interview with Abigail Thaw, you see that moment --