  Context: While star formation on large molecular cloud scales and on small
core and disk scales has been investigated intensely over the past decades, the
connection of the large-scale interstellar material with the densest
small-scale cores has been a largely neglected field.
  Methods: Using NOEMA and the IRAM 30\,m telescope, we mapped large areas
(640\,arcmin$^2$) of the archetypical star formation complex Cygnus X at
3.6\,mm wavelengths in line and continuum emission.
  Results: The scope and outline of The Cygnus Allscale Survey of Chemistry and
Dynamical Environments (CASCADE) is presented. We then focus on the first
observed subregion in Cygnus X, namely the DR20 star formation site, which
comprises sources in a range of evolutionary stages from cold pristine gas
clumps to more evolved ultracompact H{\sc ii} regions. The data covering cloud
to cores scales at a linear spatial resolution of $<5000$\,au reveal several
kinematic cloud components that are likely part of several large-scale flows
onto the central cores. The temperature structure of the region is investigated
by means of the HCN/HNC intensity ratio and compared to dust-derived
temperatures. We find that the deuterated DCO$^+$ emission is almost
exclusively located toward regions at low temperatures below 20\,K.
Investigating the slopes of spatial power spectra of dense gas tracer intensity
distributions (HCO$^+$, H$^{13}$CO$^+$, and N$_2$H$^+$), we find comparatively
flat slopes between $-2.9$ and $-2.6$, consistent with high Mach numbers and/or
active star formation in DR20.
