Human CD3⁺ T cells were isolated from peripheral blood and cultured for 72 hours in the presence of ImmunoCult™ Human CD3/CD28 T Cell Activator, followed by treatment with tumor-derived exosomes from 17 TNBC cell lines for 48 hours. After incubation, cells were harvested, washed, and stained with the TotalSeq™-C Human Universal Cocktail, v2.0 (BioLegend), which includes a panel of oligo-conjugated antibodies targeting key T cell surface markers. To enable multiplexing of biological replicates and experimental conditions, cells were also stained with TotalSeq™-C anti-human Hashtag antibodies (BioLegend), following the manufacturer's recommended titration and staining protocol. Non-coding RNAs were isolated from exosomes derived from 17 TNBC cell lines as well as from plasma samples of 28 TNBC patients and 7 healthy donors, using the MagMAX™ mirVana™ Total RNA Isolation Kit (Thermo Fisher Scientific) according to the manufacturer's protocol. The isolated RNA, enriched for small and non-coding RNAs, was quantified using a NanoDrop spectrophotometer (Thermo Fisher Scientific), and RNA quality was assessed with an Agilent Bioanalyzer 2100 (Agilent Technologies). For single cell RNA-seq, following staining, cells were counted and loaded onto the Chromium X system (10x Genomics) using the Chromium Single Cell 5′ High Throughput (HT) Immune Profiling Kit. Single-cell Gel Bead-In-Emulsions (GEMs) were generated, and barcoded cDNA libraries, including gene expression and antibody-derived tag (ADT) libraries, were constructed according to the manufacturer's instructions. The resulting libraries were sequenced on an Illumina NovaSeq 6000 platform using an S4 flow cell to a targeted depth of ~50,000 reads per cell. For noncoding RNAs, library preparation was performed using the NEXTFLEX® Small RNA-Seq Kit v4 with Unique Dual Indices (UDIs) (Revvity), which includes 3′ and 5′ adapter ligation, reverse transcription, PCR amplification, and size selection steps optimized for non-coding RNA capture. Prepared libraries were quantified using the Qubit dsDNA HS Assay Kit (Thermo Fisher Scientific) and validated for size distribution using the Agilent Bioanalyzer. Sequencing was conducted on an Illumina platform following standard procedures for small RNA libraries.