Marvel Comics, SWORD is the "Sentient World Observation and Response Department," and their very existence is a closely guarded secret. Their role is traditionally to protect the Earth from extraterrestrial threats and conduct galactic diplomacy on behalf of humanity, and they make SHIELD look like the Boy Scouts.
SWORD has been switched up for the MCU. Even the acronym has changed; the MCU's SWORD is the "Sentient Weapon Observation Response Division," a smart adjustment that moves superhumans like Scarlet Witch into their purview. Surprisingly, they've also been retconned into the fabric of the MCU as an organization that has existed for decades. This is actually the same approach Joss Whedon took when he introduced SWORD in the comics during his Astonishing X-Men run, because he simply had them step out of the shadows and start involving themselves with the affairs of the X-Men.
The broad brush-strokes of SWORD history are clearly established in WandaVision episode 4, which reveals more of its inner workings and key . Here's everything that's been confirmed about the MCU's SWORD so far.
SWORD Was Founded By Maria Rambeau After Captain Marvel
In 1995, USAF Captain Maria Rambeau discovered her best friend Carol Danvers had been granted superpowers after an encounter with aliens. The events of Captain Marvel, the Skrulls, and the Kree.
SWORD Expand Their Operations (Including Space Missions)
Maria Rambeau clearly successfully acquired significant funding, because SWORD expanded at a prodigious rate. Just as in the comics, they appear to have accumulated a significant knowledge of extraterrestrial threats, perhaps even working alongside Captain Marvel on occasion. According to WandaVision episode 4, they regularly conducted manned missions into space, and they ran their own astronaut training program. It's safe to assume SWORD had a good relationship with NASA, because although the episode avoided giving the precise location of SWORD Headquarters, the geographical landforms suggest it may be situated in Florida.
SWORD Failed To Protect The Earth From Alien Threats (Like The Chitauri)
It is reasonable to assume SWORD had successfully protected the Earth for years, and that they kept the existence of aliens a closely guarded secret. Unfortunately, though, the main Marvel movies suggest their efforts were ultimately insufficient. When Thor arrived on Earth, he was transported to the planet not by an alien spaceship, but by the Rainbow Bridge. Consequently it was not SWORD who stumbled upon him, but SHIELD. A year later, the Chitauri invasion of New York likewise blindsided SWORD, presumably because the aliens attacked via a portal. Fortunately Nick Fury brought the Avengers into play.
Monica Rambeau Was A Victim Of Thanos' Infinity War Snap
When Thanos snapped his fingers in died two years after Thanos' snap, always believing it would one day be reversed, but never seeing her daughter again.
Director Hayward Took Charge of SWORD After Maria Rambeau's Death
Director Hayward became leader of SWORD after Maria Rambeau's death. Although he was considered a logical choice, he himself noted all other potential candidates had been snapped out of existence, meaning he was the only one left. According to Hayward, SWORD's mandate changed over the next few years; the priority shifted from manned space missions to home-based threats like nanotechnology or artificial intelligence. This makes sense, because after the tragedy of the snap humanity seems to have become introverted and inward-looking, meaning funding would not have been available for further space missions. Meanwhile, it's worth noting SWORD was essentially stepping in to fill a gap that had been left by the collapse of SHIELD after Captain America: The Winter Soldier.
Hulk Reverses The Snap In Avengers: Endgame - What It Meant For SWORD
Thanos' snap plunged the galaxy into anarchy for five long years, until finally the Avengers succeeded in undoing it in the Hulk's snap was smart enough to compensate for things like space-flight when bringing everyone back, ensuring they returned safely. Still, that would have meant SWORD agents who were on missions were suddenly restored on the ground, potentially in remote locations, meaning Director Hayward would have faced the logistical nightmare of tracking everybody down. Even three weeks later, he still had missing crew. And then there would surely have been cases of pilots grieving because they realized they had been snapped out of existence, and their engers - who had not - had died in the resulting disasters.
Monica Rambeau was the first snap victim to return to active duty, still grieving the death of her mother but determined to get back to work. Director Hayward determined to follow Maria's instructions, though, and insisted Monica remain grounded pending re-evaluation. Instead of a space mission, Monica found herself assigned to meet up with FBI agent Jimmy Woo in New Jersey - and she stumbled into a reality-twisting event the likes of which even SWORD had never seen before. Soon even the SWORD agents were pulling up their chairs to watch the latest broadcasts from Westview, as they attempted to make sense of WandaVision.