review see [52], or can bring numerous uncertainties in thermal history of the universe depending on what scales they are broken. • Inflationary sector: • Graceful exit from a string landscape: It has been proven hard to embed inflationary sector within an observational sector, in most of the examples inflation and (MS)SM sectors are two distinct sectors. For all practical purposes inflaton remains in a hidden sector, whose couplings to the SM world remains unknown apriori. In a warped geometry, with multi-throats it is not clear why only the SM or MSSM throat will be dominantly excited after the end of inflation, as required for the success of BBN. Furthermore, it has been argued that during inflation the effect of back reaction would alter the compactified geometry and all the throats below the inflationary scale [883]. In a string landscape scenario, if the universe were to tunnel out of the false vacuum, then the universe would be devoid of any entropy as the nucleated bubble would keep expanding forever with a negative spatial curvature [56, 284, 876]. Such a universe would have no place in a real world. Therefore, it is important that a bubble with an MSSM like vacuum must undergo the last phase of slow-roll inflation, in order to gracefully exit the string landscape. Inflationary epoch should explain the observed temperature anisotropy and also the right degrees of freedom upon reheating [284]. Moduli are abundantly in large numbers in 4 d effective theory, which can be used to construct inflation models. The potential along the moduli remains massless in a SUSY limit. However, SUSY breaking, non-renormalizable superpotential terms, along with non- perturbative effects lift their flatness. These corrections are important to compute in order to keep the inflationary potential sufficiently flat. Some of these corrections are understood recently in the context of a KKLT scenario [55], which helps understanding the stabilization of all the complex structure moduli with the help of flux compactification [43], leaving a single volume (K¨ ahler) modulus which can be stabilized via non-perturbative effects. A. Moduli driven inflation 224