  We study the $\Xi(1620)$ resonance near the $\bar{K}\Lambda$ threshold in the
light of the recent experimental constraints. The Belle collaboration have
found a resonance peak of $\Xi(1620)$ slightly below the $\bar{K}^{0}\Lambda$
threshold in the $\pi^{+}\Xi^{-}$ invariant mass spectrum, and the ALICE
collaboration have determined the $K^{-}\Lambda$ scattering length from the
measurement of the momentum correlation functions in the heavy ion collisions.
Using the effective range expansion, we classify the nature of the pole of the
near-threshold eigenstate in terms of the scattering length, in the presence of
the decay channel. It is shown that the quasibound state below the threshold
can be described by only the scattering length, while the description of the
resonance above the threshold requires the contribution from the effective
range. Based on the chiral unitary approach, we construct a theoretical model
which generates the pole of $\Xi(1620)$ below the $\bar{K}\Lambda$ threshold
with relatively narrow width, as reported by the Belle collaboration. It is
quantitatively demonstrated that the spectrum of the $\Xi(1620)$ quasibound
state is distorted by the effect of the nearby $\bar{K}\Lambda$ threshold. We
then construct another model which reproduces the $K^{-}\Lambda$ scattering
length by the ALICE collaboration. In this case, the eigenstate pole does not
appear in the physically relevant Riemann sheets, and the spectrum shows a cusp
structure at the $\bar{K}\Lambda$ threshold. We finally examine the
compatibility of the value of the $\bar{K}\Lambda$ scattering length and the
subthreshold pole of $\Xi(1620)$ including the experimental uncertainties.
