We have obtained deep spectroscopic data in H-band of star-forming galaxies in a rich X-ray galaxy cluster at z-1.5 with Keck/MOSFIRE. Combined with our existing CO(2-1) and dust continuum data of the same galaxies obtained with ALMA (Hayashi et al. 2019), we investigate the relationship among stellar masses, metallicities, and gas masses of these cluster galaxies. We aim to put constraints on the gas inflow/outflow processes based on the chemical evolution analyses, and discuss how those processes depend on galaxy environment. I will report on the current status of this on-going work.