Interleukin-7 is critical for T-cell development and displays antimicrobial and antitumor properties. It is referred to as a "critical enhancer of protective immunity". However, there is no information on interleukin-7 dynamics following colorectal surgery. Moreover, although robot-assisted surgery is gaining popularity, data on the immune response to it is almost non-existent. In this prospective non-randomized case-control study we found interleukin-7 dynamics to differ following robot-assisted and open approach and to affect postoperative immunity. Linear increases were seen in the robotic group while a cubic pattern with a maximum at 8 h in the open one. Low preoperative interleukin-7 was associated with developing surgical site infection. In turn, higher preoperative interleukin-7 was associated with preserved immune function: less pronounced drop in lymphocyte count and higher Δlymphocyte/Δneutrophil ratio in patients undergoing robotic surgery. The changes in other cytokines, namely, interleukin-12(p70), TNFα, interferon-γ, and interleukin-10 were independently associated with interleukin-7 dynamics. In turn, relative changes in interleukin-7 were independent predictors of changes in interferon-γ, key cytokine of favourable Th1 immune response. Taken together, we demonstrated different perioperative dynamics of interleukin-7, which may contribute to favourable outcomes following robotic colorectal surgery including lower incidence of surgical site infections, milder surgery-induced lymphopenia, and beneficial interferon-γ dynamics.