The goals of heavy-ion collision experiments is to study the properties of nuclear matter at extreme conditions. According to lattice QCD, at high temperature and high energy density, the ordinary nuclear matter may undergo a phase transition, called Quark-Gluon Plasma (QGP) phase. This QGP is believed to exist few micro-second after Big-Bang and currently at the core of neutron stars. Correlation and fluctuations study is regarded as one of the probes to understand the thermodynamics of the QGP medium. In this presentation, I will discuss my research work on the experimental measurements of fluctuations of conserved charges, which is an excellent tool to map the QCD phase diagram. Moreover, I will discuss my R&D work for the silicon pixel detector upgrade in the ALICE experiment at the LHC for the high luminosity run in 2021.