The effects of high-temperature, dense systems, and strong magnetic fields on Quantum Chromodynamics related phenomena are studied in different perspectives: in the high-temperature and densities, the QCD-phase diagram from the Linear Sigma Model point of view is computed. In particular, the CEP location and transition lines for chiral restoration were found. In the intense magnetic fields and high-gluon density, the gluon fusion and gluon splitting channels are proposed as new photon production sources to better explain the experimental data in the so-called photon puzzle. Finally, the thermal and magnetic screening properties for gluons encoded into the polarization tensor were addressed in terms of the Debye mass.