Willie Nelson is probably the best example of the fusion of country and western. When he first went to Nashville they were blending but still marketed as two separate genres. He failed as a traditional country singer in Nashville but had a very successful career as a songwriter and wrote many of the hit country songs of the 50s and 60s. It wasn't until he retired and moved back to Austin that he became successful as a singer. He discovered alternative country artists like Merle Haggard and started writing for and performing with them. He used his connections to recruit some other popular country artists like Johnny Cash and Waylon Jennings and to get deals with record labels and that was the birth of Outlaw County which was the first popular country and western crossover genre.
The origins of country music was Appalachian folk music. The earliest albums were literally just families sitting on their front porches singing with one or two of them playing instruments. It's origins are the stories of the lived experience of an impoverished people frequently experiencing exploitation for lumber and coal. When Willie started collaborating with Snoop he pointed out that county, and especially outlaw county, and gangster rap originated from similar places and used a lot of the same themes.