Femtoscopy is an experimental method used to study the spatial and temporal characteristics of the particle-emitting “sources” of ultra-relativistic particle collisions. This method allows us to measure the size, shape, and lifetime of the kinetic freeze-out region of the particles created in the Heavy-Ion collisions. Studying these source regions allows us to investigate the dynamics of the system as it evolves from the hot, dense state of matter known as the Quark-Gluon Plasma. The femtoscopic correlation is measured for both Lamba (AntiLambda) and kshort in 2018 PbPb collision at 5.02 TeV. The data sample was collected by CMS experiments at the LHC. Since both neutral kaons and lambdas are neutral particles, the correlations are not affected by Coulomb interactions but might be sensitive to the effects of strong interactions. By measuring Lambda (AntiLambda) - Lambda (AntiLambda) correlation, we can look for an exotic particle called H-dibaryon(six quark state "uuddss") predicted by R. L. Jaffe in1976. In this talk, I will discuss some of my analysis preliminary results obtained in Pb-Pb collisions.​ ​