Simulations of the Indian summer monsoon (ISM) have greatly improved over the years, especially during the last decade, due to concerted efforts by the numerical modeling community, aided by better observations and supercomputers. However, there still remain many challenges associated with ISM modeling that need to be addressed in due course. This talk will present some of the important precipitation biases over the South Asian Monsoon region in the CMIP5/CMIP6 models, followed by the impact of some recent process improvements in the convection scheme of a global model. Specifically, the impact of changes to the convective time scale and atmospheric mixing processes on some of the ISM biases will be discussed. Finally, some challenges and gaps in ISM modeling will be briefly touched upon.