Cosmological observations are in very good agreement with an universe that is expanding, spatially flat, homogeneous and isotropic on large scales where the large scale structures originated from primordial perturbations with a nearly gaussian and scale-invariant spectrum. On the theoretical side, the paradigm of slow-roll inflation, a period of accelerated expansion in the early history of the universe, predicts such a primordial spectrum starting with the fluctuations of the inflaton field. In general there are two dynamical realisation of the inflationary dynamics: Cold inflation and Warm inflation. In this talk, I will explain this two dynamical realisations of inflation. The constraints from the observations by Planck satellite has ruled out most of the so called text book cold inflation potentials such as quartic potential. I will explain even a quartic potential in warm inflationary paradigm can survive the tight constraints from observations. Finally, I would try to explore the future course of research in this field.