Persistent antigen exposure leads to the accumulation of lymphocytes and subsequent tertiary lymphoid structures (TLS). We investigated the relationship of tumor microenvironment (TME) with respect to programmed death ligand 1 (PD-L1), its receptor programmed death 1 (PD-1), and TLS in upper tract urothelial carcinoma (UTUC) cases and compared them with UTUC associated with urothelial bladder carcinoma (UTUC-BCa).