Final Fantasy VII Remake is the first part of a much larger story. This has resulted in an unusual casualty, as Final Fantasy VII Remake is the first mainline entry in the series to not include a character named Cid since the original Final Fantasy back on the NES.
The Final Fantasy series has a number of recurring elements, including chocobos, moogles, tonberries, airships, and the summon monsters. One of the most well-known recurring elements of the series is the inclusion of a character named Cid. This started in Final Fantasy II when an airship pilot named Cid helped ferry Firion and his party around the world. A second Cid appeared in Final Fantasy III, and another in Final Fantasy IV... and so on. There have been Cids in every mainline entry in the series, as well as in almost every spin-off. The original Final Fantasy even retroactively added a Cid in the remakes of the game, and he went on to have a role in the Dissidia series.
Final Fantasy VII had a Cid named Cid Highwind, who was a member of the party and the group's resident airship pilot/mechanic. Cid doesn't join the group until the party reaches Rocket Town, which takes place long after the Midgar section of the game. The fact that Final Fantasy VII Remake only covers the Midgar section of the story means that Cid doesn't appear at all, nor is he mentioned.
Some fans speculated that Cid would have a brief cameo role in the game, even if he wasn't playable, as what happened with Cait Sith, but that never came to pass. It would have been easy to include a scene with Cid visiting Midgar to hassle Palmer or President Shinra about funding for the space program, but it wasn't meant to be. This means that Final Fantasy VII Remake is the first mainline entry in the series to not include a Cid since the late '80s.
Final Fantasy VII Remake will have a different story from its predecessor, but Cid Highwind and the Highwind airship are almost guaranteed to appear. It's likely that Square Enix will release a Final Fantasy VII Remake Definitive Edition in years to come that includes all of the entries in a single game, which could retroactively tie Cid into the events of the first entry.
But for now, we have a Cidless Final Fantasy game.