Carrimycin is a potential immune-regulating agent for sepsis in patients with tumors. In this study, we investigated its effects on inflammation and immune function in tumor patients with sepsis. In total, 120 participants were randomized to receive either carrimycin treatment (400 mg/day) (n = 62) or placebo (n = 58) for 7 days. The primary outcomes were immune-related indicators. Subsequently, patients were stratified into two subgroups (CD4 < 38.25% and CD8 < 25.195%). Ninety-nine participants were analyzed: 47 and 52 in the carrimycin and placebo groups, respectively. HLA-DR levels were rapidly increased in the carrimycin group; however, the placebo group initially experienced a decline in HLA-DR level at 1 day after administration. In the subgroup with CD4