Maoism is an adaptation of Marxist-Leninism. In
Mao's case he adapted a theory that was originally developed within the context of a relatively advanced industrializing society, Europe of the 19th century, to a context of an almost purely aggricultural society--China of the early and mid 20th century.
Mao was a military genious, if not a political one, for his development of a
protracted 'peoples war.' Whether you like him or not, and there is a lot not to like, his military theory was victorious and continues to be emulated today as well as studied by the students of
West Point etc.