Identify the prognostic value and investigate the association between programmed cell death 1 (PDCD1) gene expression and immune infiltration in pan-cancer.We used a series of bioinformatics methods to comprehensively analyze the relationship between PDCD1 gene and prognosis, tumor mutational burden (TMB), microsatellite instability (MSI), immune cell infiltration of various cancers from the existing public database, and try to find the potential prognostic value of PDCD1 for in pan-cancer.High expression of PDCD1 was closely related to better overall survival (OS) and disease-specific survival (DSS) in breast invasive carcinoma, head and neck squamous cell carcinoma, skin cutaneous melanoma, and uterine corpus endometrial carcinoma; have a better disease-free interval (DFI) and progression-free interval (PFI) in several cancer types. Meanwhile, the high level of PDCD1 gene expression was associated with poorer OS, DSS, and PFI in brain lower grade glioma and uveal melanoma; poorer OS in acute myeloid leukemia and kidney renal papillary cell carcinoma; poorer OS and DSS in glioblastoma multiforme; poorer DSS in kidney renal clear cell carcinoma, by Kaplan-Meier and Cox survival analysis. PDCD1 gene expression was significantly correlated with TMB and MSI in 14 and 12 cancer types, respectively, and infiltrating levels of immune cells, especially Macrophages M0, M1, CD4-T-cells, CD8-T-cells, and T cells follicular helper, in most of eight cancer types.PDCD1 can be used as a prognostic marker in multiple cancers, owing to it is closely associated with TMB, MSI, and immune cells infiltration.Copyright © 2020 Elsevier B.V. All rights reserved.