"Wake up, Chief...I need you!" After four years, seven months, and ten days Cortana finally calls on John...
The ending has a tiny little moment where John and Lasky are looking down at the Earth from orbit. Lasky amused by John calling him sir tries to break the awkwardness of being John's superior by starting some idle chit chat, talking about the beauty of the Earth before realizing that John isn't much for small talk. He then tries to comfort him about the the loss of Cortana, only for John to mechanically reply that, as a soldier, it's his job to protect humanity regardless of the cost. Lasky finds this dismissive of John's own humanity and reminds him that he is more than a soldier, a machine, but a person. John muses on this for a moment, remembers something that Cortana told him before she died, and then goes to have his suit removed after years of constant service, being laid bare not as a soldier but as a man for the first time.
Essentially, every moment spent with Cortana is a combination of this and Tear Jerker, and it culminates in Cortana finally getting to physically touch Chief before she passes on.
It is a little heartwarming to know that the former covenant races are accepted enough to be allowed to immigrate to Earth, even as some Sanghieli see it as a vector for terrorism.