PCA of the training, testing, and total SCLC cohort demonstrated a different distribution pattern of high risk and low risk based on 10 immune‐related gene expression, indicating their difference in immune phenotype (Figure 3), the training set was clustered and heatmap was created (Figure 4), and the NR3C1, NR1D2, and TANK gene expression levels were higher in high‐risk population, while ARAF, HDGF, INHBE, LRSAM1, PLXNA1, PML, and SP1 gene expression levels were higher in low‐risk population (Figure 4). Here, HDGF is linked to small cell lung carcinoma.