PDCD1 and cancer: The development of pH‐selective VISTA antibodies in immune checkpoint‐based cancer therapy is currently still unknown; however, anti‐VISTA mAbs (e.g. the novel SNS‐101 anti‐VISTA mAb; Sensei Biotherapeutics, Inc.)may potentiate anti‐PD‐1/PD‐L1‐induced antitumor immunity.