The CD8 + T cells could enhance response of antitumor immune in cancers. Therefore, we aimed to analyze the CD8 + T cells related genes in small cell lung cancer (SCLC) patients. The data of SCLC samples were collected from the Gene Expression Omnibus database. The hub genes were screened by weighted gene co-expression network analysis, protein-protein interaction network and survival analyses. Moreover, the relative proportions of the 22 immune cells in the samples were calculated using CIBERSORT software. The relationship between target gene and immunotherapy was analyzed in IMvigor210 cohort. We identified 10 genes (PTPRC, RPS27A, UBA52, CD8A, ITGB2, GNB2L1, TYROBP, CD86, TLR4, and FCGR3A) that were correlated with CD8 + T cells in SCLC. Among them, ITGB2 was positively correlated with CD8 + T cells in SCLC. ITGB2 was down-regulated in SCLC. SCLC patients with low ITGB2 expression exhibited a poor prognosis, and ITGB2 was an independent prognostic factor for survival rate of SCLC patients. The differentially expressed genes between ITGB2high and ITGB2low groups were significantly enriched in 143 signaling pathways. We also discovered that the ImmuneScore, StromalScore, and the expression of immune checkpoints (PD-1 (PDCD1), CTLA4, PDL-1 (CD274), TIGIT, IFNG, GZMA, TBX2, and IDO1) were significantly increased in ITGB2high group. Moreover, SCLC patients with high ITGB2 expression had lower tumor immune dysfunction and exclusion scores, and the proportion of urothelial cancer patients with complete response/partial response was observably decreased in ITGB2high group. Finally, we found that ITGB2 was correlated with IC50 of cancer drugs. In conclusion, SCLC patients with low ITGB2 expression exhibited worse prognosis. ITGB2 might be correlated with immunotherapy response of SCLC patients.