It's a series of crimsims in the style of GTA: San Andreas. At least the first two were. Saints Row 1 is the most grounded of the bunch and the closest to San Andreas: a crime drama intercut with some wacky stuff here and there. The game's also only available on XBLA, which is why it's not widely talked about. Saints Row 2 cranks the wacky bullshit up quite a bit, which can result in you doing a mission that ends with an emotional cutscene in which you performing a mercy kill on one of your mangled homies... only to hop into a septic truck and spray shit on people's houses to drive down real estate value in the next. It's on Steam, but the port is one of the most legendarily shitty ports to still technically be functional and even fan-made patches won't do it any good.You know, I've always wondered something: If this game series was so great, why is it that I have never heard anything about it except for the occasional mention of the name in a list on PirateBay? What is it about, and why does nobody ever care to speak of it?
Saints Row The Third cranks up the wacky bullshit even more and sees the titular Saints having gone corporate and become slaves to PR, only to be taken down a peg and ending up having to rebuild to face a powerful cartel of gangs and a security force bordering on being a PMC. It pretends to be a serious crime drama while having you compete in a murderous wacky Japanese game show and pilot flying motorcycles. Seeing the Saints forget where they came from, getting too big for their britches and suffering the consequences for it is an apt metaphor for what happened to the series, but the developers either missed out on the parallels or just didn't care.
Saints Row IV... well, it starts with the Saints sneaking into a foreign military base, the boss jumping onto a nuclear missile and defusing it while riding it into the sky while Aerosmith's "I don't wanna miss a thing" plays in the background. It works, the day is saved and the boss gets elected President of the United States for the trouble. Then aliens invade and shove you into the Matriix, which is the exact same city from the previous game. You manage to escape and now have to jack into the not-Matrix to rescue your homies and stop the aliens, all the while developing superpowers while inside. Note that this is same series that started with you being saved from being collateral damage in a gang shootout and you joining to make the streets a safer place in the first game. And don't get me started on Gat out of Hell...
Even though the third game sold the best, the first two games (especially the second) are held in the highest regard by the fans for being the best games in the series for being crime dramas with just the right amount of wacky. The third and fourth go way overboard, especially the fourth. And since we haven't had new games in the series for well over half a decade, discussion slowed down to a crawl until there was news of the new game, and... it looks like it's going to be a woke trash fire.