A large investigation has found that most patients receiving lifesaving cellular therapies develop hidden blood pressure drops upon standing within their first month. The study links a majority incidence of orthostatic hypotension—falls in blood pressure after standing—to the early post-infusion window. Orthostatic hypotension matters because it can translate into dizziness, falls, and acute care escalation during a period when patients are already vulnerable to infection risk and immune complications. The findings provide a clinically actionable monitoring target for transplant and CAR-T-like pathways. Clinicians can use the results to tighten early vital-sign surveillance and guide supportive management protocols after cellular therapy initiation.