For instance, Gu and co-workers have fabricated a HA-based hydrogel reservoir used for encapsulating CAR-T cells and anti-PD-L1-conjugated platelets, which could efficiently inhibit post-surgery melanoma tumor recurrence (Fig. 11a–c).380 The encapsulated CAR-T cells displayed good survivability, proliferation, and bioactivity for targeting human chondroitin sulfate proteoglycan 4 that was selectively highly expressed in melanoma cells rather than healthy cells. This evidence concerns the gene CD274 and melanoma.