Plant nucleotide binding and leucine-rich repeat (NLR) receptors mediate the specific recognition of pathogen effectors, which in turn triggers defense responses against invading pathogens. NLRs play a central role in plant immunity and are primarily composed of coiled coil NLRs (CNLs) and toll-interleukin 1 receptor NLRs (TNLs). However, the signaling mechanisms of plant NLRs have only recently started to be understood. The process of pathogen effector recognition can involve direct or indirect interactions with plant NLRs, resulting in the oligomerization of these receptors and consequent the formation of large protein complexes known as resistosomes. In the case of CNL resistosomes, their primary function is to serve as calcium-permeable channels that initiate NLR-mediated immunity. The channel activity of CNLs has been demonstrated to be evolutionarily conserved. By comparison, TNL resistosomes function as NADase holoenzymes, catalyzing the production of nucleotide-derived small molecules. Structural and biochemical evidence revealed that these small molecules act as second messengers, consequently activating the assembly and channel activity of resistosomes of helper NLRs, which are a subgroup of the CNL family. In this presentation, I will be providing evidence on how plant NLRs assemble into resistosomes in response to pathogen effectors and how these NLR resistosomes ultimately converge on calcium signals.