This review article explores the synergistic signal mechanisms between Pattern-Triggered Immunity (PTI) and Effector-Triggered Immunity (ETI) in plant immunity. Plants face a constant threat from pathogens, and have evolved a multi-tiered immune system that includes both PTI and ETI. PTI is the first line of defense, where cell surface pattern recognition receptors (PRRs) detect conserved microbial patterns, initiating a rapid response to potential threats. ETI is a more specialized and robust defense mechanism that targets specific pathogen effectors, often resulting in a localized hypersensitive response to halt infection. PTI and ETI work together synergistically to enhance disease resistance and trigger a cascade of downstream defense responses. PRRs, such as receptor-like kinases (RLKs) and receptor-like proteins (RLPs), recognize conserved elicitors from pathogens or endogenous molecules released during pathogen invasion. NLRs, on the other hand, detect pathogen effectors inside host cells and activate ETI. The interaction between PTI and ETI involves a cascade of signaling events, including the generation of reactive oxygen species (ROS) and calcium ion fluxes, which serve as critical second messengers in the plant's immune response. These signaling pathways are intricately linked, with PTI often priming the plant for a more potent ETI response. The molecular dialogue between PTI and ETI is further modulated by a suite of transcription factors and hormone signaling pathways, which together orchestrate a coordinated defense against a diverse array of pathogens. Despite significant advances in understanding plant immunity, the precise mechanisms underlying the crosstalk between PTI and ETI, as well as their integration with other plant defense responses, remain areas of active research. This review aims to provide a comprehensive overview of the current knowledge on the stepwise activation of endogenous immunity in plants, focusing on the recognition of extracellular and intracellular effectors by PRRs and NLRs. The review emphasizes the complex interplay between these pathways and their contributions to the overall plant immune response.This review article explores the synergistic signal mechanisms between Pattern-Triggered Immunity (PTI) and Effector-Triggered Immunity (ETI) in plant immunity. Plants face a constant threat from pathogens, and have evolved a multi-tiered immune system that includes both PTI and ETI. PTI is the first line of defense, where cell surface pattern recognition receptors (PRRs) detect conserved microbial patterns, initiating a rapid response to potential threats. ETI is a more specialized and robust defense mechanism that targets specific pathogen effectors, often resulting in a localized hypersensitive response to halt infection. PTI and ETI work together synergistically to enhance disease resistance and trigger a cascade of downstream defense responses. PRRs, such as receptor-like kinases (RLKs) and receptor-like proteins (RLPs), recognize conserved elicitors from pathogens or endogenous molecules released during pathogen invasion. NLRs, on the other hand, detect pathogen effectors inside host cells and activate ETI. The interaction between PTI and ETI involves a cascade of signaling events, including the generation of reactive oxygen species (ROS) and calcium ion fluxes, which serve as critical second messengers in the plant's immune response. These signaling pathways are intricately linked, with PTI often priming the plant for a more potent ETI response. The molecular dialogue between PTI and ETI is further modulated by a suite of transcription factors and hormone signaling pathways, which together orchestrate a coordinated defense against a diverse array of pathogens. Despite significant advances in understanding plant immunity, the precise mechanisms underlying the crosstalk between PTI and ETI, as well as their integration with other plant defense responses, remain areas of active research. This review aims to provide a comprehensive overview of the current knowledge on the stepwise activation of endogenous immunity in plants, focusing on the recognition of extracellular and intracellular effectors by PRRs and NLRs. The review emphasizes the complex interplay between these pathways and their contributions to the overall plant immune response.