When fever and imaging suggest infection but every targeted test returns empty-handed, the clinician is left holding suspicion without proof — a familiar impasse in the care of immunocompromised and transplant patients. Next-generation sequencing reframes the diagnostic question itself, shifting from 'is this specific pathogen here?' to 'what is actually present?' by reading the entire microbial landscape at once. This technological turn, embodied in platforms capable of identifying hundreds of fungal and bacterial species simultaneously, represents a quiet but consequential evolution in how m