International audienceNIKA2 is a dual-band millimetric camera of thousands of Kinetic InductanceDetectors (KID) installed at the IRAM 30-meter telescope in the Spanish SierraNevada. The instrument commissioning was completed in September 2017, and NIKA2is now open to the scientific community and will operate for the next decade.NIKA2 has well-adapted instrumental design and performance to produce high-resolution maps of the thermal Sunyaev-Zel'dovich (SZ) effect towardintermediate and high redshift galaxy clusters. Moreover, it benefits from aguaranteed time large program dedicated to mapping a representative sample ofgalaxy clusters via SZ and that includes X-ray follow-ups. The main expectedoutputs of the SZ large program are the constraints on the redshift evolution ofthe pressure profile and the mass-observable relation. The first SZ mapping of agalaxy cluster with NIKA2 was produced, as part of the SZ large program. Wefound a sizable impact of the intracluster medium dynamics on the integrated SZobservables. This shows NIKA2 capabilities for the precise characterisation ofthe mass-observable relation that is required for accurate cosmology with galaxyclusters