NF-κB signaling, first identified in 1986, has evolved from a key player in inflammatory responses to a multifaceted regulator of various biological processes, diseases, and therapeutic targets. This review summarizes the composition, activation, and regulation of NF-κB signaling, its interactions with other pathways such as PI3K/AKT, MAPK, JAK-STAT, TGF-β, Wnt, Notch, and TLR, and its roles in inflammation, immunity, and tumor microenvironments. It also explores NF-κB's involvement in diseases like cancer, autoimmune disorders, and cardiovascular conditions, and discusses therapeutic strategies targeting NF-κB, including inhibitors, monoclonal antibodies, and immunotherapies. The review highlights the dual nature of NF-κB as both a "foe" and "friend," emphasizing the need for a comprehensive understanding of its mechanisms to inform future research and clinical applications. The canonical and non-canonical NF-κB pathways are detailed, along with their activation, regulation, and interactions with other signaling pathways. The review underscores the importance of NF-κB in cellular processes such as proliferation, survival, and immune responses, and its potential as a therapeutic target in various diseases. The complex interplay between NF-κB and other signaling pathways is discussed, highlighting the need for integrated approaches to understand and manipulate NF-κB signaling for therapeutic benefit.NF-κB signaling, first identified in 1986, has evolved from a key player in inflammatory responses to a multifaceted regulator of various biological processes, diseases, and therapeutic targets. This review summarizes the composition, activation, and regulation of NF-κB signaling, its interactions with other pathways such as PI3K/AKT, MAPK, JAK-STAT, TGF-β, Wnt, Notch, and TLR, and its roles in inflammation, immunity, and tumor microenvironments. It also explores NF-κB's involvement in diseases like cancer, autoimmune disorders, and cardiovascular conditions, and discusses therapeutic strategies targeting NF-κB, including inhibitors, monoclonal antibodies, and immunotherapies. The review highlights the dual nature of NF-κB as both a "foe" and "friend," emphasizing the need for a comprehensive understanding of its mechanisms to inform future research and clinical applications. The canonical and non-canonical NF-κB pathways are detailed, along with their activation, regulation, and interactions with other signaling pathways. The review underscores the importance of NF-κB in cellular processes such as proliferation, survival, and immune responses, and its potential as a therapeutic target in various diseases. The complex interplay between NF-κB and other signaling pathways is discussed, highlighting the need for integrated approaches to understand and manipulate NF-κB signaling for therapeutic benefit.