The subgroup analysis of Gal-9 level on cancer cells in combination with PD-1, PD-L1, CD3, CD4, CD8, and FOXP3, respectively, showed no significant difference among different groups, which indicated the failure of Gal-9 on tumor cells in predicting the RFS in SCLC (online supplemental figure S2). Here, CD8A is linked to small cell lung carcinoma.