Neuroinflammation is a key component in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Microglia and astrocytes, the primary glial cells in the central nervous system, play crucial roles in regulating inflammatory responses. These cells can be activated into neurotoxic (M1/M2-phenotype microglia and A1/A2-phenotype astrocytes) or neuroprotective states. However, the dichotomized classification of these phenotypes may not fully capture the complexity of their functions. The activation of microglia and astrocytes is influenced by various factors, including genetic, environmental, and endogenous factors, and can lead to neurodegeneration. Understanding the roles of microglia and astrocytes in neurodegenerative diseases is essential for developing effective therapies. This review discusses the inflammatory responses in neurodegenerative diseases, focusing on the contributions of microglia and astrocytes, their relationships, and biomarkers for measuring neuroinflammation. Additionally, it explores therapeutic drugs that can modulate neuroinflammation. The complexity of microglial and astrocyte phenotypes and the need for specific clinical trials to evaluate the benefits of anti-inflammatory treatments are also highlighted.Neuroinflammation is a key component in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Microglia and astrocytes, the primary glial cells in the central nervous system, play crucial roles in regulating inflammatory responses. These cells can be activated into neurotoxic (M1/M2-phenotype microglia and A1/A2-phenotype astrocytes) or neuroprotective states. However, the dichotomized classification of these phenotypes may not fully capture the complexity of their functions. The activation of microglia and astrocytes is influenced by various factors, including genetic, environmental, and endogenous factors, and can lead to neurodegeneration. Understanding the roles of microglia and astrocytes in neurodegenerative diseases is essential for developing effective therapies. This review discusses the inflammatory responses in neurodegenerative diseases, focusing on the contributions of microglia and astrocytes, their relationships, and biomarkers for measuring neuroinflammation. Additionally, it explores therapeutic drugs that can modulate neuroinflammation. The complexity of microglial and astrocyte phenotypes and the need for specific clinical trials to evaluate the benefits of anti-inflammatory treatments are also highlighted.