This paper provides a comprehensive review of NOMA-aided cell-free massive MIMO (CF-mMIMO) systems. The authors analyze the fundamentals of massive MIMO (mMIMO), CF-mMIMO, and NOMA, and present a state-of-the-art review of NOMA-aided CF-mMIMO. They discuss the challenges and potential of integrating CF-mMIMO with other enabling technologies to enhance performance. The paper highlights the benefits of combining NOMA with CF-mMIMO, including increased data rates, reliability, and security. It also addresses the challenges of NOMA with CF-mMIMO, such as pilot contamination and the need for efficient channel estimation. The paper concludes with a discussion of key findings and possible future research directions. The authors emphasize the importance of NOMA in future wireless communication systems, particularly for 6G networks, and suggest that further research is needed to fully realize the potential of NOMA-aided CF-mMIMO systems.This paper provides a comprehensive review of NOMA-aided cell-free massive MIMO (CF-mMIMO) systems. The authors analyze the fundamentals of massive MIMO (mMIMO), CF-mMIMO, and NOMA, and present a state-of-the-art review of NOMA-aided CF-mMIMO. They discuss the challenges and potential of integrating CF-mMIMO with other enabling technologies to enhance performance. The paper highlights the benefits of combining NOMA with CF-mMIMO, including increased data rates, reliability, and security. It also addresses the challenges of NOMA with CF-mMIMO, such as pilot contamination and the need for efficient channel estimation. The paper concludes with a discussion of key findings and possible future research directions. The authors emphasize the importance of NOMA in future wireless communication systems, particularly for 6G networks, and suggest that further research is needed to fully realize the potential of NOMA-aided CF-mMIMO systems.