The historical multi-messenger firework SN1987A confirmed the importance of neutrinos in a core-collapse supernova. However, there has been no confirmed supernova neutrinos since, leaving many open questions in stellar collapse. The diffuse flux of supernova neutrinos provides an immediate opportunity to detect stellar core-collapse neutrinos. This signal is spatially isotropic and temporally constant, arising from the combined fluxes of neutrinos emitted from all distant stellar core collapses. It has not been detected yet, but the Super-Kamiokande detector, now upgraded with gadolinium, has a real shot at its first discovery. In this talk, I will review predictions of the diffuse supernova neutrino flux and discuss the detection prospects in the coming decade. Inputs from both the theoretical, observational, and experimental communicates are crucial, and I will cover recent insights gained from both simulations and observational surveys. I will close with some promising probes which would become possible in the precision phase during the Hyper-Kamiokande era.