The ending of Ghost War closes Crown's plan, exposes Spear, and puts Greer at the top of the CIA with Jack recommended as his deputy. Crown is dead and his network's data is in the team's hands. Emma recovers from her wound, and Andrew Spear faces punishment for his betrayal. Greer becomes CIA Director and recommends Jack as Deputy Director, and the two walk into CIA headquarters together.
What was Crown actually trying to do? He planted evidence for MI6 to find so that the terror groups Starling once shut down would stir again, and then Starling's brutal methods would look justified. Our read is that that makes him a more interesting villain than a plain bomber, because his argument depends on Greer's own past. The London Bridge threat is the decoy, and Jack is the real target, which is why Greer is left exposed.
Perhaps the neatest touch is Spear. Crown reached Nigel's secret apartment before Jack did, so somebody on the inside had to let him in, and that points straight at Emma's boss. Arguably, the film plays fair here, since the clue is set up well before Spear is revealed.
How does it compare with the earlier films? London is the obvious link to Patriot Games (1992), where Ryan stepped in to stop an attack on Lord Holmes and made an enemy in Sean Miller. There the danger followed Ryan home as a personal revenge story, whereas in Ghost War the danger is built from Greer's secrets and Ryan is a target by design. We would say that makes Ghost War the more political of the two. The Hunt for Red October (1990) is the other useful yardstick: Ryan was the analyst who read a man's record correctly and Greer was the veteran boss in the background. Here Greer is the one with the buried past, and Jack has to clean it up.
The final scene also echoes Clear and Present Danger (1994), in which Ryan was made acting deputy director of intelligence while Greer was treated for cancer. Here Greer recommends Jack for the Deputy Director post as the two walk into headquarters, after Jack has spent the film cleaning up Greer's secret. No sequel is officially greenlit, though Krasinski has said he would like to continue the character in films. Our next jack ryan movie page tracks any announcement.