Table 1. Baseline characteristics of the study population (n = 321).

Parameter		n	% of non-missing values
Sex	Male sex	251	78
	Female sex	70	22
Smoking status	Non-smoker	61	20
	Smoker or ex-smoker	252	81
Performance status	ECOG 0	59	19
	ECOG I	235	76
	ECOG >II	16	5
Adjuvant therapy	Adjuvant chemotherapy	8	3
	Adjuvant radiotherapy	38	12
Tumor stage	Stage I	187	58
	Stage II	83	26
	Stage III	51	16
Tumor size	pT1	99	31
	pT2	192	60
	pT3	19	6
	pT4	11	3
Lymph nodes status	pN0	202	63
	pN1-3	117	37
Tumor histology	Squamous cell carcinoma	149	46
	Adenocarcinoma	125	39
	Large cell carcinoma	47	15
Tumor grading	G1	5	2
	G2	111	35
	G3-4	199	63
Apoptosis	Negative Bcl-2 expression	231	76
	Positive Bcl-2 expression	74	24
	Negative Bcl-xl expression	196	66
	Positive Bcl-xl expression	101	34
EGFR mutation status	No EGFR mutation	22	79
	EGFR mutation	6	21
Proliferation (ki-67)	Negative ki-67 expression	77	24
	Positive ki-67 expression	244	76
PD-1 expression in tumor Infiltrating lymphocytes (TILs)	negative lymphocytic expression	249	78
	negative lymphocytic expression	72	22
PD-L1 expression in NSCLC	negative tumor expression	244	76
	positive tumor expression	77	24