  The aim of this work is to study the anisotropic weak lensing signal
associated with the mass distribution of massive clusters of galaxies using the
Cosmic Microwave Background (CMB) data. For this purpose, we stack patches of
the Planck Collaboration 2018 CMB lensing convergence map centered on SDSS DR8
redMaPPer clusters within the redshift range [0.4, 0.5]. We obtain mean radial
profiles of the convergence parameter k finding strong signals at scales as
large as 40 Mpc/h. By orienting the clusters along their major axis defined
through the galaxy member distribution, we find a significant difference
between the parallel and perpendicular oriented convergence profiles. The
amplitude of the profile along the parallel direction is about 50% larger than
that along the perpendicular direction, indicating that the clusters are well
aligned with the surrounding mass distribution. From a model with an
anisotropic surface mass density, we obtain a suitable agreement for both mass
and ellipticities of clusters compared to results derived from weak lensing
shear estimates, finding strong evidence of the correlation between the galaxy
cluster member distribution and the large--scale mass distribution.
