Immune signaling is the academic field and biological concept investigating the complex molecular and cellular mechanisms by which immune cells perceive stimuli, transmit information internally and externally, and orchestrate immune responses. This area of study encompasses receptor-ligand interactions, intracellular signal transduction cascades, and the subsequent transcriptional and functional changes that govern immune cell activation, differentiation, and communication, underpinning host defense, tolerance, and immune-related pathologies.