The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment operated at about 10\,mK reaching the ton-scale. CUORE main goal is the search for neutrinoless double beta decay in $^{130}$Te, while it is suitable also for other kinds of rare event searches, such as dark matter and axions. The detector is situated at Laboratori Nazionali del Gran Sasso (LNGS), Italy, and consists in an array of 988 TeO$_2$ crystals, being both the detector and the source of the decay. Since the beginning of 2017, CUORE operations had both phases for physics data taking and campaigns of detector optimization to obtain the maximum from its potential. Here we briefly discuss one of the procedures for the optimization of the detector regarding noise reduction and report the achievements of CUORE concerning energy resolution and background in the region of interest after the first few months of data taking. Finally we conclude by examining the results from our first neutrinoless double beta decay analysis published at the beginning of 2018, which with a total TeO$_2$ exposure of 86.3 kg$\cdot$y allowed to place a lower limit on the decay half-life of $T^{0\nu}_{1/2}(^{130}\mathrm{Te})>1.3\times10^{25}\,{\rm yr}$ (90% C.L.) .