All of the five immune protein markers, namely CD4 (HR = 0.57; 95% CI: 0.31-1.06, P = 0.047), CD3 (HR = 0.51; 95% CI: 0.29-0.9, P = 0.013), Gal-9 on tumor cells (HR=1.83; 95% CI: 1.01-3.31, P = 0.029), PD-1 (HR = 3.37; 95% CI: 1.86-6.09, P = 0.003), and PD-L1 on tumor cells (HR = 2.1; 95% CI: 1.19-3.72, P = 0.007) predicted survival in patients with LCNEC. Here, CD4 is linked to large cell neuroendocrine carcinoma.