The project CUPID is an upgrade of the CUORE experiment, aiming at searching for neutrinoless double beta (0νββ) decay with Li2MoO4 scintillating crystals enriched in 100Mo. The crystals are operated as cryogenic detectors in the zero-background condition for its entire life cycle, which provides the fastest increase of sensitivity over the data collection time. The zero background condition is achievable via the particle discrimination in the scintillation channel.