Statistical methods
Microsoft Excel 2017 (Microsoft, Redmond, WA, USA) was used to establish
the database, and SPSS version 24.0 statistical software (IBM Corp.,
Armonk, NY, USA) was used to analyze the differences among the groups.
The chi-squared test was used to compare frequency data between groups,
and the differences between groups was considered to be statistically
significant when P < 0.05. The immunohistochemical staining
scores for CD3, CD4, CD8, PD-1, and PD-L1 in the 36 patients were
analyzed.