Immunological Variables Associated to ICI Toxicity in Cancer Patients

This is a monocentric, prospective, pilot study that will enrol 435 subjects with solid tumours that are treated with immune checkpoint inhibitor(s) (ICI) alone or in combination with chemotherapy or targeted therapy. For enrolled subjects, clinical and laboratory evaluations will be performed and reported at different time points: * Early (4-6 weeks after treatment start) * Midtime (8-11 weeks after treatment start) * Late (13-18 weeks after treatment start) * At the occurrence of immune-related adverse events (irAEs), clinical and laboratory evaluation will be performed at two principal time points: * For the 1st time of any grade 1 or 2 irAE if the subject developed it. * For the 1st time of any grade 3 or 4 irAE if the subject developed it.