The DEA (Drug Enforcement Administration, the US agency that controls which drugs are legal) cannot move psilocybin or MDMA off the most restricted category unless the FDA (the US drug regulator) first approves them as medicine. Since no FDA approval exists yet, the legal status stays frozen. This means anyone caught with these substances still faces serious federal criminal consequences.
DEA rescheduling is procedurally gated on completed FDA approval plus an HHS abuse-potential review. With no FDA approval in hand, the statutory trigger for the eight-factor review is absent, so Schedule I status holds.