Pulmonary hypertension (PH) is a complex and multifactorial disease characterized by increased pulmonary arterial pressure, leading to right ventricular hypertrophy and ultimately heart failure. Inflammation plays a pivotal role in the pathogenesis of PH and can be induced by various etiologies, such as chemical reagent, hypoxia, pulmonary artery obstructions, and infectious agents such as bacteria, viruses, and parasites. Some etiologies trigger an aseptic inflammatory cascade involving macrophages, monocytes, eosinophils, neutrophils, and other immune cells, alongside endothelial cells, smooth muscle cells, and fibroblasts. Infectious inflammation in PH, caused by bacteria, viruses, and parasites like Schistosoma, further complicates the disease landscape by engaging both immune and nonimmune cells in the inflammatory process. This review aims to provide a comprehensive overview of the immune and nonimmune intercellular responses involved in these different forms of inflammation associated with PH. Understanding the intricate interactions networks between immune and nonimmune cells in the inflammation underlying PH is essential for developing targeted therapies and improving patient outcomes. This review highlights the diverse cellular mechanisms contributing to the inflammation of PH and underscores the need for further research to elucidate the precise pathways and interactions driving this debilitating condition.