library_construction_protocol: Renal tumor samples were dissociated into single cells by a semi-automated combined mechanical/enzymatic process. The tumor tissue was cut into pieces of (2-3mm) in size and transferred to C Tubes (Miltenyi Biotech) containing a mix of Enzymes H, R and A (Tumor Dissociation Kit, human; Miltenyi Biotech). Mechanical dissociation was accomplished by performing a program (37C_h_TDK_1) on the gentleMAC Octo Dissociator with Heaters (Miltenyi Biotech). Single cell suspensions generated from ccRCC tumor samples were FACS sorted on a SONY MA900 sorter (SONY) for viable human CAR-T cells (Zombie- mCD45- hCD45+ CD3+, BioLegend). Sorted cells were stained with a distinct barcoded antibody (Cell-Hashing antibody, TotalSeq-A, Biolegend). Next, 7,500 cells from each condition were resuspended in 0.4% BSA in PBS at a concentration of 1,000 cells per μl, pooled together, then loaded onto a single lane (Chromium chip B, 10X Genomics) followed by encapsulation in a lipid droplet (Single Cell 5′ kit V3, 10X Genomics) followed by cDNA and library generation according to the manufacturer's protocol. mRNA library was sequenced to an average of 50,000 reads per cell, and HTO (Cell Hashing antibodies) library sequenced to an average of 5,000 reads per cell, both using Illumina Novaseq.