Pulmonary hypertension (PH) is a progressive disease characterized by increased pulmonary vascular pressure, leading to right heart failure. Recent evidence highlights the critical role of immune cells and inflammation in PH development. Immune cells, including T cells, macrophages, B cells, dendritic cells, and neutrophils, infiltrate the pulmonary vasculature, increasing cytokine and chemokine levels, which contribute to vascular remodeling. T helper cells (Th1, Th17) and regulatory T cells (Tregs) play key roles in inflammation and immune regulation. Th17 cells promote inflammation, while Tregs suppress it. Macrophages contribute to vascular remodeling by secreting pro-inflammatory factors. B cells and dendritic cells also influence immune responses and vascular inflammation. Cytokines such as IL-1β, IL-6, IL-10, and TNF-α are involved in PH pathogenesis, with IL-6 promoting vascular remodeling and fibrosis. Chemokines like CCL2, CCL5, and CX3CL1 mediate immune cell recruitment and vascular inflammation. Vascular cells and BMPR2 are central to immune regulation and vascular remodeling. Immunosuppressive therapies, including B-cell depletion and anti-inflammatory agents, show promise in treating PH. Understanding immune mechanisms and inflammation in PH is crucial for developing effective therapeutic strategies. This review summarizes the role of immune cells and inflammation in PH, highlighting potential therapeutic targets.Pulmonary hypertension (PH) is a progressive disease characterized by increased pulmonary vascular pressure, leading to right heart failure. Recent evidence highlights the critical role of immune cells and inflammation in PH development. Immune cells, including T cells, macrophages, B cells, dendritic cells, and neutrophils, infiltrate the pulmonary vasculature, increasing cytokine and chemokine levels, which contribute to vascular remodeling. T helper cells (Th1, Th17) and regulatory T cells (Tregs) play key roles in inflammation and immune regulation. Th17 cells promote inflammation, while Tregs suppress it. Macrophages contribute to vascular remodeling by secreting pro-inflammatory factors. B cells and dendritic cells also influence immune responses and vascular inflammation. Cytokines such as IL-1β, IL-6, IL-10, and TNF-α are involved in PH pathogenesis, with IL-6 promoting vascular remodeling and fibrosis. Chemokines like CCL2, CCL5, and CX3CL1 mediate immune cell recruitment and vascular inflammation. Vascular cells and BMPR2 are central to immune regulation and vascular remodeling. Immunosuppressive therapies, including B-cell depletion and anti-inflammatory agents, show promise in treating PH. Understanding immune mechanisms and inflammation in PH is crucial for developing effective therapeutic strategies. This review summarizes the role of immune cells and inflammation in PH, highlighting potential therapeutic targets.