Statistical methods
SPSS version 25 was used for all statistical methods in this study, and the evaluation of the group receiving immunotherapy and the group not receiving immunotherapy (including progressive disease, stable disease, and partial response), the evaluation of the group receiving domestic or imported immune checkpoint inhibitors, as well as the evaluation of the different NLR level groups were taken by the Chi-square test, and the Fisher’s exact test was taken when the frequency number was less than 5,P <0.05 was considered statistically different. Kaplan-Meier survival analysis was used to plot the survival curves of different factor groups respectively; Cox univariate survival analysis was used to identify the important factors affecting the PFS of colorectal cancer patients among several factors respectively, and then Cox multivariate survival analysis was used to correct and identify the factors affecting the prognosis among the above factors, and the same was considered as statistically different with P <0.05.