Similar to that in the cohort of young patients, the prognosis of all LUAD patients and lung cancer patients could be predicted by CD28 (P = 0.0011; P < 0.0001), PD-L1 (P = 0.0002; P = 0.0001) and CD3 (P = 0.0004; P < 0.0001), as shown in Fig. 3. Here, CD28 is linked to lung cancer.