Abstract: Pulmonary fibrosis (PF) is a lung disease with a very poor prognosis that seriously affects the quality of life of patients and is characterized by scarring and thickening of the tissue surrounding the alveolar walls, ultimately leading to respiratory failure. Currently, the Food and Drug Administration (FDA) approved drugs for the treatment of PF include pirfenidone and nidazanib, however, these two drugs can only delay the progression of the disease but cannot achieve the reversal of PF, and their clinical application is limited due to high price and multiple adverse effects. The pathogenesis of PF has not been fully elucidated, and studies have demonstrated that aberrant immune cell activation and regulation play an important role in PF. This review aims to discuss the role of immune cell activation and regulation in PF in recent years. The aim of this review is to discuss recent advances in the study of the role of immune cells in the process of PF, with the aim of providing theoretical guidance for the development of novel immunotherapies.