Power Rangers is the western adaptation of a series called Super Sentai. It uses the same suits as the Japanese original and reworks some footage, while adding and changing things via a new cast of Western, multiracial actors, occasionally turning a male Yellow Ranger into a girl, and just adapting and translating it.
Super Sentai started in the late 70s, but about 7-ish years earlier, Toei, with the help of a guy named Shotaro Ishinomori, made Kamen Rider, about a guy who was forcibly turned into a cyborg by an evil organization to be used as a weapon, but was released by a moral scientist and started fighting against them.
Kamen Rider continued throughout the 70s and into the 80s, took a haitus aside from some movies in the 90s, and got started right as the millennia swapped over, where it's been running as the slightly-more-dramatic older brother of Sentai. It varies on the year, obviously, sometimes you have comedic series, sometimes more dark ones, but instead of focusing on a team of 5-6 who have roughly equal footing, Rider tends towards smaller casts of combatants, usually with a hierarchy where the MC gets the lion's share of the cool toys, the secondary gets a bit less, then a tertiary with even less, etc.